Systems and methods for establishing reliable wireless links

ABSTRACT

A first device such as a wristwatch may include a front face at which a display is disposed and a rear face at which a rear housing wall is mounted. Antenna structures may overlap the rear housing wall and may be operable to transmit and receive relatively high frequency signals through the rear housing wall to a communication with a second device such as a wireless power transmitting device for the wristwatch. The second device may also include antenna structures that overlap a top surface housing. Respective sets of magnetic structures may be provided in the first and second devices to align the two devices and to form a reliable wireless communication link between the two devices. The first and second devices may include respective antenna arrays that include pairs of antenna elements that are selectively used to form a reliable wireless communication link.

This application is a continuation application of U.S. patentapplication Ser. No. 16/584,700 filed on Sep. 26, 2019. This applicationclaims the benefit of and claims priority to U.S. patent applicationSer. No. 16/584,700, which is hereby incorporated by reference herein inits entirety.

BACKGROUND

This relates to electronic devices, and more particularly, to electronicdevices with wireless circuitry.

Electronic devices are often provided with wireless communicationscapabilities. Because wireless circuitry such as antennas have thepotential to interfere with each other and with other components in awireless device, care must be taken when incorporating antennas into anelectronic device to ensure that the antennas and other wirelesscircuitry are able to exhibit satisfactory performance over a wide rangeof operating frequencies.

In some applications, it is desirable to incorporate wireless circuitrythat allows for relatively high rates of data transfer. However,operations of the wireless circuitry at relatively high frequencies,such as at frequencies of about 10-300 GHz, that allow for high datarate data transfer can raise significant challenges. As an example,signal polarization misalignment between communicating devices anddirectional misalignment between communicating devices often degradewireless communication links between the communicating devices.

It would therefore be desirable to be able to provide improved wirelesscircuitry and interfacing circuitry for electronic devices.

SUMMARY

An electronic device, such as a wristwatch or a wireless power receivingdevice, may have front and rear faces. A display having a display coverglass may be disposed at the front face and a rear housing wall (e.g.,rear housing member) may be disposed at rear face. One or more antennaresonating elements for an antenna may overlap the rear housing wall andthat is operable to transmit radio-frequency signals through the rearhousing wall. The one or more antenna resonating elements may for anantenna array for the electronic device. Radio-frequency transceivercircuitry (e.g., near-field communications circuitry) may be coupled tothe one or more antenna resonating elements and may be operable to usethe one or more antenna resonating elements to transmit radio-frequencysignals above 10 GHz through the rear housing wall. If desired, theradio-frequency transceiver circuitry may be operable use only a subsetof the antenna resonating elements in the antenna array and/or may beoperable to use a pair of the antenna resonating elements in the antennaarray at a time.

As an example, the one or more antenna resonating elements may be formedat a substrate in a backside circuitry module (e.g., a sensor module).The radio-frequency transceiver circuitry may be mounted to thesubstrate. As another example, the one or more antenna resonatingelements may be formed at a printed circuit substrate to which theradio-frequency transceiver circuitry and control circuitry thatcontrols an operation of the radio-frequency transceiver circuitry aremounted. As yet another example, an additional antenna resonatingelement for an additional antenna may overlap the rear housing wall andmay be operable to transmit additional radio-frequency signals throughthe rear housing wall. The one or more antenna resonating elements maybe aligned with one or more corresponding antenna apertures defined atleast in part by the additional antenna resonating element.

If desired, the antenna resonating elements in the antenna array mayoverlap the rear housing wall along in a circumferential path about acentral axis of the wristwatch. As an example, the rear housing wall hasa protruding portion and the circumferential path may overlap theprotruding portion. As another example, the rear housing wall may have aplanar portion and the circumferential path may overlap the protrudingportion.

In some embodiments, alignment structures may be disposed at the rearhousing wall and may be configured to apply a force through the rearhousing wall. The alignment structures may include first and secondmagnetic structures that apply magnetic forces through the rear housingwall. The first and second magnetic structures may be configured to biasthe rear housing wall to equipment external to the electronic device(e.g., a wireless power transmitting device) and to align the antennaresonating element to the external equipment. The attachment structuresmay have first and second portions (e.g., the first and second magneticstructures), and the sensor module and coil structures are interposedbetween the first and second portions of the attachment structures.

The electronic device may wirelessly communicate with wireless powertransmitting equipment. The wireless power transmitting equipment mayinclude a housing, a coil structure, wireless power transmittingcircuitry coupled to the coil structures and configured to use the coilstructure to convey wireless power signals through a portion of thehousing. The wireless power transmitting equipment may also include aplurality of antenna elements for an antenna array useable byradio-frequency transceiver circuitry to convey radio-frequency signalsabove 10 GHz through the portion of the housing.

As an example, the antenna array may be operable to sequentially userespective antenna elements in pairs of antenna elements in theplurality of antenna elements at a time to receive additionalradio-frequency signals. Control circuitry may be configured to receivewireless performance information based on the additional radio-frequencysignals received from the respective antenna elements in the pairs ofantenna elements. The control circuitry may be operable to select one ormore antenna elements in the plurality of antenna elements for conveyingthe radio-frequency signals based on the received wireless performanceinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative electronic device withwireless circuitry in accordance with some embodiments.

FIG. 2 is a schematic diagram of an illustrative electronic device withwireless circuitry in accordance with some embodiments.

FIG. 3 is a diagram of illustrative wireless circuitry in an electronicdevice in accordance with some embodiments.

FIG. 4 is a cross-sectional side view of an illustrative electronicdevice having antenna elements overlapping a rear housing wall inaccordance with some embodiments.

FIG. 5 is a diagram of an illustrative dipole antenna element inaccordance with some embodiments.

FIG. 6 is a diagram of two illustrative devices that perform high datarate wireless communication operations in accordance with someembodiments.

FIG. 7 is a bottom-up view of a first electronic device having antennaelements and attachment structures that overlap a rear housing wall inaccordance with some embodiments.

FIG. 8 is a top-down view of a second electronic device having antennaelements and attachment structures that are configured to align withantenna elements and attachment structures in a first electronic devicesuch as the first electronic device of FIG. 7 in accordance with someembodiments.

FIG. 9 is a bottom-up view of a first electronic device having an arrayof antenna elements that overlap a rear housing wall in accordance withsome embodiments.

FIG. 10 is a top-down view of a second electronic device having an arrayof antenna elements that are configured to align with an array ofantenna elements in a first electronic device such as the firstelectronic device shown in FIG. 9 in accordance with some embodiments.

FIG. 11 is an illustrative flowchart for establishing a wirelesscommunication link between first and second electronic devices inaccordance with some embodiments.

FIG. 12 is a diagram of illustrative states for an electronic devicesuch as one of the electronic devices shown in FIGS. 8 and 10 inaccordance with some embodiments.

DETAILED DESCRIPTION

Electronic devices such as electronic device 10 of FIG. 1 may beprovided with wireless circuitry (sometimes referred to herein aswireless communications circuitry). The wireless circuitry may be usedto support wireless communications in multiple wireless communicationsbands. Communications bands (sometimes referred to herein as frequencybands) handled by the wireless circuitry can include satellitenavigation system communications bands, cellular telephonecommunications bands, wireless local area network communications bands,wireless personal area network communications bands, near-fieldcommunications bands, ultra-wideband communications bands, centimeterwave communications bands, millimeter wave communications bands, orother wireless communications bands.

The wireless circuitry may include one or more antennas. The antennas ofthe wireless circuitry can include loop antennas, inverted-F antennas,strip antennas, planar inverted-F antennas, patch antennas, slotantennas, monopole antennas, dipole antennas, hybrid antennas thatinclude antenna structures of more than one type, or other suitableantennas.

Electronic device 10 may be a computing device such as a laptopcomputer, a computer monitor containing an embedded computer, a tabletcomputer, a cellular telephone, a media player, or other handheld orportable electronic device, a smaller device such as a wristwatchdevice, a pendant device, a headphone or earpiece device, a deviceembedded in eyeglasses or other equipment worn on a user's head, orother wearable or miniature device, a television, a computer displaythat does not contain an embedded computer, a gaming device, anavigation device, an embedded system such as a system in whichelectronic equipment with a display is mounted in a kiosk or automobile,equipment that implements the functionality of two or more of thesedevices, or other electronic equipment. In the illustrativeconfiguration of FIG. 1 , device 10 is a portable device such as awristwatch (e.g., a smart watch). Other configurations may be used fordevice 10 if desired. The example of FIG. 1 is merely illustrative.

In the example of FIG. 1 , device 10 includes a display such as display14. Display 14 may be mounted in a housing such as housing 12. Housing12, which may sometimes be referred to as an enclosure or case, may beformed of plastic, glass, ceramics, fiber composites, metal (e.g.,stainless steel, aluminum, etc.), other suitable materials, or acombination of any two or more of these materials. Housing 12 may beformed using a unibody configuration in which some or all of housing 12is machined or molded as a single structure or may be formed usingmultiple structures (e.g., an internal frame structure, one or morestructures that form exterior housing surfaces, etc.). Housing 12 mayhave metal sidewalls such as sidewalls 12W or sidewalls formed fromother materials. Examples of metal materials that may be used forforming sidewalls 12W include stainless steel, aluminum, silver, gold,metal alloys, or any other desired conductive material. Sidewalls 12Wmay sometimes be referred to herein as housing sidewalls 12W orconductive housing sidewalls 12W.

Display 14 may be formed at (e.g., mounted on) the front side (face) ofdevice 10. Housing 12 may have a rear housing wall on the rear side(face) of device 10 such as rear housing wall 12R that opposes the frontface of device 10. Conductive housing sidewalls 12W may surround theperiphery of device 10 (e.g., conductive housing sidewalls 12W mayextend around peripheral edges of device 10). Rear housing wall 12R maybe formed from conductive materials and/or dielectric materials.Examples of dielectric materials that may be used for forming rearhousing wall 12R include plastic, glass, sapphire, ceramic, wood,polymer, combinations of these materials, or any other desireddielectrics.

Rear housing wall 12R and/or display 14 may extend across some or all ofthe length (e.g., parallel to the X-axis of FIG. 1 ) and width (e.g.,parallel to the Y-axis) of device 10. Conductive housing sidewalls 12Wmay extend across some or all of the height of device 10 (e.g., parallelto the Z-axis of FIG. 1 ). Conductive housing sidewalls 12W and/or rearhousing wall 12R may form one or more exterior surfaces of device 10(e.g., surfaces that are visible to a user of device 10) and/or may beimplemented using internal structures that do not form exterior surfacesof device 10 (e.g., conductive or dielectric housing structures that arenot visible to a user of device 10 such as conductive structures thatare covered with layers such as thin cosmetic layers, protectivecoatings, and/or other coating layers that may include dielectricmaterials such as glass, ceramic, plastic, or other structures that formthe exterior surfaces of device 10 and/or serve to hide housing walls12R and/or 12W from view of the user).

Display 14 may be a touch screen display that incorporates a layer ofconductive capacitive touch sensor electrodes or other touch sensorcomponents (e.g., resistive touch sensor components, acoustic touchsensor components, force-based touch sensor components, light-basedtouch sensor components, etc.) or may be a display that is nottouch-sensitive. Capacitive touch screen electrodes may be formed froman array of indium tin oxide pads or other transparent conductivestructures. Display 14 may also be force sensitive and may gather forceinput data associated with how strongly a user or object is pressingagainst display 14.

Display 14 may include an array of display pixels formed from liquidcrystal display (LCD) components, an array of electrophoretic displaypixels, an array of plasma display pixels, an array of organiclight-emitting diode (OLED) display pixels, an array of electrowettingdisplay pixels, or display pixels based on other display technologies.Display 14 may be protected using a display cover layer. The displaycover layer may be formed from a transparent material such as glass,plastic, sapphire or other crystalline dielectric materials, ceramic, orother clear materials. The display cover layer may extend acrosssubstantially all of the length and width of device 10, for example.

Device 10 may include buttons such as button 18. There may be anysuitable number of buttons in device 10 (e.g., a single button, morethan one button, two or more buttons, five or more buttons, etc.).Buttons may be located in openings in housing 12 (e.g., openings inconductive housing sidewall 12W or rear housing wall 12R) or in anopening in display 14 (as examples). Buttons may be rotary buttons,sliding buttons, buttons that are actuated by pressing on a movablebutton member, etc. Button members for buttons such as button 18 may beformed from metal, glass, plastic, or other materials. Button 18 maysometimes be referred to as a crown in scenarios where device 10 is awristwatch device.

Device 10 may, if desired, be coupled to a strap such as strap 16. Strap16 may be used to hold device 10 against a user's wrist (as an example).Strap 16 may sometimes be referred to herein as wrist strap 16. In theexample of FIG. 1 , wrist strap 16 is connected to opposing sides ofdevice 10. Conductive housing sidewalls 12W may include attachmentstructures for securing wrist strap 16 to housing 12 (e.g., lugs orother attachment mechanisms that configure housing 12 to receive wriststrap 16). Configurations that do not include straps may also be usedfor device 10.

A schematic diagram showing illustrative components that may be used indevice 10 is shown in FIG. 2 . As shown in FIG. 2 , device 10 mayinclude control circuitry 28. Control circuitry 28 may include storagesuch as storage circuitry 24. Storage circuitry 24 may include hard diskdrive storage, nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form asolid-state drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc.

Control circuitry 28 may include processing circuitry such as processingcircuitry 26. Processing circuitry 26 may be used to control theoperation of device 10. Processing circuitry 26 may include on one ormore microprocessors, microcontrollers, digital signal processors, hostprocessors, baseband processor integrated circuits, application specificintegrated circuits, central processing units (CPUs), etc. Controlcircuitry 28 may be configured to perform operations in device 10 usinghardware (e.g., dedicated hardware or circuitry), firmware, and/orsoftware. Software code for performing operations in device 10 may bestored on storage circuitry 24 (e.g., storage circuitry 24 may includenon-transitory (tangible) computer readable storage media that storesthe software code). The software code may sometimes be referred to asprogram instructions, software, data, instructions, or code. Softwarecode stored on storage circuitry 24 may be executed by processingcircuitry 26.

Control circuitry 28 may be used to run software on device 10 such asexternal node location applications, satellite navigation applications,internet browsing applications, voice-over-internet-protocol (VOIP)telephone call applications, email applications, media playbackapplications, operating system functions, etc. To support interactionswith external equipment, control circuitry 28 may be used inimplementing communications protocols. Communications protocols that maybe implemented using control circuitry 28 include internet protocols,wireless local area network protocols (e.g., IEEE 802.11protocols—sometimes referred to as Wi-Fi®), protocols for othershort-range wireless communications links such as the Bluetooth®protocol or other wireless personal area network (WPAN) protocols, IEEE802.11ad protocols, cellular telephone protocols, MIMO protocols,antenna diversity protocols, satellite navigation system protocols(e.g., global positioning system (GPS) protocols, global navigationsatellite system (GLONASS) protocols, etc.), IEEE 802.15.4ultra-wideband communications protocols or other ultra-widebandcommunications protocols, data transfer protocols, etc. Eachcommunications protocol may be associated with a corresponding radioaccess technology (RAT) that specifies the physical connectionmethodology used in implementing the protocol.

Data transfer protocols handled by control circuitry 28 (sometimesreferred to herein as data bus protocols) may be used to perform highdata rate data transfer operations (e.g., data transfer operations atspeeds of 100 Megabits per second (Mbps) or more, at 500 Mbps or more, 1bit per second or more, etc.). Data transfer protocols that may beimplemented by control circuitry 28 may include Universal Serial Bus(USB) protocols, universal asynchronous receiver/transmitter (UART)protocols, Peripheral Component Interconnect (PCI) protocols, PeripheralComponent Interconnect Express (PCIe) protocols, Accelerated GraphicsPort (AGP) protocols, or any other desired data transfer protocolscapable of data speeds (i.e., data rates) of greater than or equal toapproximately 100 Mbps.

Device 10 may include input-output circuitry 20. Input-output circuitry20 may include input-output devices 22. Input-output devices 22 may beused to allow data to be supplied to device 10 and to allow data to beprovided from device 10 to external devices. Input-output devices 22 mayinclude user interface devices, data port devices (e.g., test portdevices), and other input-output components. For example, input-outputdevices 22 may include touch screens, displays without touch sensorcapabilities, buttons, scrolling wheels, touch pads, key pads,keyboards, microphones, cameras, buttons, speakers, status indicators,light sources, audio jacks and other audio port components, vibrators orother haptic feedback engines, digital data port devices, light sensors(e.g., infrared light sensors, visible light sensors, etc.),light-emitting diodes, motion sensors (accelerometers), capacitancesensors, proximity sensors, magnetic sensors, force sensors (e.g., forcesensors coupled to a display to detect pressure applied to the display),etc.

Input-output circuitry 22 may include wireless circuitry 34. Wirelesscircuitry 34 may include wireless power receiving coil structures suchas coil structures 44 and wireless power receiver circuitry such aswireless power receiver circuitry 42. Device 10 may use wireless powerreceiver circuitry 42 and coil structures 44 to receive wirelesslytransmitted power (e.g., wireless charging signals) from a wirelesspower adapter (e.g., a wireless power transmitting device such as awireless charging mat or other device). Coil structures 44 may includeone or more inductive coils that use resonant inductive coupling (nearfield electromagnetic coupling) with a wireless power transmitting coilon the wireless power adapter.

The wireless power adapter may pass AC currents through the wirelesspower transmitting coil to produce a time varying electromagnetic (e.g.,magnetic) field that is received as wireless power (wireless chargingsignals) by coil structures 44 in device 10. An illustrative frequencyfor the wireless charging signals is 200 kHz. Other frequencies may beused, if desired (e.g., frequencies in the kHz range, the MHz range, orin the GHz range, frequencies of 1 kHz to 1 MHz, frequencies of 1 kHz to100 MHz, frequencies less than 100 MHz, frequencies less than 1 MHz,etc.). When the time varying electromagnetic field is received by coilstructures 44, corresponding alternating-current (AC) currents areinduced in the coil structures. Wireless power receiver circuitry 42 mayinclude converter circuitry such as rectifier circuitry. The rectifiercircuitry may include rectifying components such as synchronousrectification metal-oxide-semiconductor transistors arranged in a bridgenetwork, and may convert these currents from coil structures 44 into aDC voltage for powering device 10. The DC voltage produced by therectifier circuitry in wireless power receiver circuitry 42 can be usedin powering (charging) an energy storage device such as battery 46 andcan be used in powering other components in device 10.

To support wireless communications, wireless circuitry 34 may includeradio-frequency (RF) transceiver circuitry formed from one or moreintegrated circuits, power amplifier circuitry, low-noise inputamplifiers, passive RF components, one or more antennas such asantenna(s) 40, transmission lines, and other circuitry for handling RFwireless signals. Wireless signals can also be sent using light (e.g.,using infrared communications).

Wireless circuitry 34 may include radio-frequency transceiver circuitryfor handling various radio-frequency communications bands. For example,wireless circuitry 34 may include wireless local area network (WLAN) andwireless personal area network (WPAN) transceiver circuitry 32.Transceiver circuitry 32 may handle 2.4 GHz and 5 GHz bands for WiFi®(IEEE 802.11) communications or other WLAN bands and may handle the 2.4GHz Bluetooth® communications band or other WPAN bands. Transceivercircuitry 32 may sometimes be referred to herein as WLAN/WPANtransceiver circuitry 32.

Wireless circuitry 34 may use cellular telephone transceiver circuitry36 for handling wireless communications in frequency ranges(communications bands) such as a cellular low band (LB) from 600 to 960MHz, a cellular low-midband (LMB) from 1410 to 1510 MHz, a cellularmidband (MB) from 1710 to 2170 MHz, a cellular high band (HB) from 2300to 2700 MHz, a cellular ultra-high band (UHB) from 3300 to 5000 MHz, orother communications bands between 600 MHz and 5000 MHz or othersuitable frequencies (as examples). Cellular telephone transceivercircuitry 36 may handle voice data and non-voice data.

Wireless circuitry 34 may include satellite navigation system circuitrysuch as Global Positioning System (GPS) receiver circuitry 30 forreceiving GPS signals at 1575 MHz or for handling other satellitepositioning data (e.g., GLONASS signals at 1609 MHz). Satellitenavigation system signals for receiver circuitry 30 are received from aconstellation of satellites orbiting the earth. Wireless circuitry 34can include circuitry for other short-range and long-range wirelesslinks if desired. For example, wireless circuitry 34 may includecircuitry for receiving television and radio signals, paging systemtransceivers, near field communications (NFC) transceiver circuitry 38(e.g., an NFC transceiver operating at 13.56 MHz or another suitablefrequency), etc.

In some configurations that are sometimes described herein as anexample, near-field communications circuitry 38 may include transceivercircuitry operable at frequencies above about 10 GHz (e.g., atfrequencies between about 10 GHz and 300 GHz), and are sometimesreferred to herein as millimeter/centimeter wave transceiver circuitry.The millimeter/centimeter wave transceiver circuitry may supportcommunications in Extremely High Frequency (EHF) or millimeter wavecommunications bands between about 30 GHz and 300 GHz and/or incentimeter wave communications bands between about 10 GHz and 30 GHz(sometimes referred to as Super High Frequency (SHF) bands). As anexample, near-field communications circuitry 38 may includemillimeter/centimeter wave transceiver circuitry operable at about 60GHz (or any frequency in a millimeter/centimeter wave frequency band) toestablish a wireless link useable for data transfer operations (e.g.,between device 10 as a wristwatch and a computer, between device 10 as awristwatch and another electronic device, between device 10 as a firstelectronic device and a second electronic device, etc.). If desired,near-field communications circuitry 38 may include radio-frequencytransceiver circuitry operable at a frequency lower than 10 GHz toestablish a wireless link usable for data transfer. In someconfigurations, non-near-field communications circuitry may be used tosupport communications in Extremely High Frequency (EHF) or millimeterwave communications bands between about 30 GHz and 300 GHz and/or incentimeter wave communications bands between about 10 GHz and 30 GHz.Wireless data transfer protocols may be used by transceiver circuitry 38to bidirectionally transfer data at these frequencies.

In NFC links, wireless signals are typically conveyed over a few inchesat most (e.g., less than five inches, less than four inches, less thanthree inches, etc.). In satellite navigation system links, cellulartelephone links, and other long-range links, wireless signals aretypically used to convey data over thousands of feet or miles. In WLANand WPAN links at 2.4 and 5 GHz and other short-range wireless links,wireless signals are typically used to convey data over tens or hundredsof feet. Antenna diversity schemes may be used if desired to ensure thatthe antennas that have become blocked or that are otherwise degraded dueto the operating environment of device 10 can be switched out of use andhigher-performing antennas used in their place.

Wireless circuitry 34 may include antennas 40. Antennas 40 may be formedusing any suitable antenna types. For example, antennas 40 may includeantennas with resonating elements that are formed from slot antennastructures, loop antenna structures, patch antenna structures, stackedpatch antenna structures, antenna structures having parasitic elements,inverted-F antenna structures, planar inverted-F antenna structures,helical antenna structures, monopole antennas, dipole antennastructures, Yagi (Yagi-Uda) antenna structures, surface integratedwaveguide structures, hybrids of these designs, etc. If desired, one ormore of antennas 40 may be cavity-backed antennas or reflector-backedantennas.

Different types of antennas may be used for different bands andcombinations of bands. For example, one type of antenna may be used informing a local wireless link antenna whereas another type of antenna isused in forming a remote wireless link antenna. If desired, space may beconserved within device 10 by using a single antenna to handle two ormore different communications bands. For example, a single antenna 40 indevice 10 may be used to handle communications in a WiFi® or Bluetooth®communication band at 2.4 GHz, a GPS communications band at 1575 MHz, aWiFi® or Bluetooth® communications band at 5.0 GHz, and one or morecellular telephone communications bands such as a cellular low bandbetween about 600 MHz and 960 MHz and/or a cellular midband betweenabout 1700 MHz and 2200 MHz. If desired, a combination of antennas forcovering multiple frequency bands and dedicated antennas for covering asingle frequency band may be used.

It may be desirable to implement at least some of the antennas in device10 using portions of electrical components that would otherwise not beused as antennas and that support additional device functions. As anexample, it may be desirable to induce antenna currents in componentssuch as display 14 (FIG. 1 ), so that display 14 and/or other electricalcomponents (e.g., a touch sensor, near-field communications loopantenna, conductive display assembly or housing, conductive shieldingstructures, etc.) can serve as part of an antenna for Wi-Fi, Bluetooth,GPS, cellular frequencies, and/or other frequencies without the need toincorporate separate bulky antenna structures in device 10. Conductiveportions of housing 12 (FIG. 1 ) may be used to form part of an antennaground for one or more antennas 40.

A schematic diagram of wireless circuitry 34 is shown in FIG. 3 . Asshown in FIG. 3 , wireless circuitry 34 may include transceivercircuitry 48 (e.g., cellular telephone transceiver circuitry 36 of FIG.2 , WLAN/WPAN transceiver circuitry 32 of FIG. 2 , near-fieldcommunications transceiver circuitry 36 of FIG. 2 , etc.) that iscoupled to a given antenna 40 using a radio-frequency transmission linepath such as radio-frequency transmission line path 50.

To provide antenna structures such as antenna 40 with the ability tocover different frequencies of interest, antenna 40 may be provided withcircuitry such as filter circuitry (e.g., one or more passive filtersand/or one or more tunable filter circuits). Discrete components such ascapacitors, inductors, and resistors may be incorporated into the filtercircuitry. Capacitive structures, inductive structures, and resistivestructures may also be formed from patterned metal structures (e.g.,part of an antenna). If desired, antenna 40 may be provided withadjustable circuits such as tunable components that tune the antennaover communications (frequency) bands of interest. The tunablecomponents may be part of a tunable filter or tunable impedance matchingnetwork, may be part of an antenna resonating element, may span a gapbetween an antenna resonating element and antenna ground, etc.

Radio-frequency transmission line path 50 may include one or moreradio-frequency transmission lines (sometimes referred to herein simplyas transmission lines). Radio-frequency transmission line path 50 (e.g.,the transmission lines in radio-frequency transmission line path 50) mayinclude a positive signal conductor such as signal conductor 52 and aground signal conductor such as ground conductor 54.

The transmission lines in radio-frequency transmission line path 50 may,for example, include coaxial cable transmission lines (e.g., groundconductor 54 may be implemented as a grounded conductive braidsurrounding signal conductor 52 along its length), striplinetransmission lines (e.g., where ground conductor 54 extends along twosides of signal conductor 52), a microstrip transmission line (e.g.,where ground conductor 54 extends along one side of signal conductor52), coaxial probes realized by a metalized via, edge-coupled microstriptransmission lines, edge-coupled stripline transmission lines, waveguidestructures (e.g., coplanar waveguides or grounded coplanar waveguides),combinations of these types of transmission lines and/or othertransmission line structures, etc.

Transmission lines in radio-frequency transmission line path 50 may beintegrated into rigid and/or flexible printed circuit boards. In onesuitable arrangement, radio-frequency transmission line path 50 mayinclude transmission line conductors (e.g., signal conductors 52 andground conductors 54) integrated within multilayer laminated structures(e.g., layers of a conductive material such as copper and a dielectricmaterial such as a resin that are laminated together without interveningadhesive). The multilayer laminated structures may, if desired, befolded or bent in multiple dimensions (e.g., two or three dimensions)and may maintain a bent or folded shape after bending (e.g., themultilayer laminated structures may be folded into a particularthree-dimensional shape to route around other device components and maybe rigid enough to hold its shape after folding without being held inplace by stiffeners or other structures). All of the multiple layers ofthe laminated structures may be batch laminated together (e.g., in asingle pressing process) without adhesive (e.g., as opposed toperforming multiple pressing processes to laminate multiple layerstogether with adhesive).

A matching network may include components such as inductors, resistors,and capacitors used in matching the impedance of antenna 40 to theimpedance of radio-frequency transmission line path 50. Matching networkcomponents may be provided as discrete components (e.g., surface mounttechnology components) or may be formed from housing structures, printedcircuit board structures, traces on plastic supports, etc. Componentssuch as these may also be used in forming filter circuitry in antenna(s)40 and may be tunable and/or fixed components.

Radio-frequency transmission line path 50 may be coupled to antenna feedstructures associated with antenna 40. As an example, antenna 40 mayform an inverted-F antenna, a planar inverted-F antenna, a patchantenna, a loop antenna, a dipole antenna, or other antenna having anantenna feed 56 with a positive antenna feed terminal such as terminal58 and a ground antenna feed terminal such as terminal 60. Positiveantenna feed terminal 58 may be coupled to an antenna resonating(radiating) element within antenna 40. Ground antenna feed terminal 60may be coupled to an antenna ground in antenna 40. Signal conductor 52may be coupled to positive antenna feed terminal 58 and ground conductor54 may be coupled to ground antenna feed terminal 60.

Other types of antenna feed arrangements may be used if desired. Forexample, antenna 40 may be fed using multiple feeds each coupled to arespective port of transceiver circuitry 48 over a correspondingtransmission line. If desired, signal conductor 52 may be coupled tomultiple locations on antenna 40 (e.g., antenna 40 may include multiplepositive antenna feed terminals coupled to signal conductor 52 of thesame radio-frequency transmission line path 50). Switches may beinterposed on the signal conductor between transceiver circuitry 48 andthe positive antenna feed terminals if desired (e.g., to selectivelyactivate one or more positive antenna feed terminals at any given time).The illustrative feeding configuration of FIG. 3 is merely illustrative.

Device 10 may include multiple antennas that convey radio-frequencysignals through different sides of device 10. For example, device 10 mayinclude at least a first antenna that conveys radio-frequency signalsthrough the front face of device 10 (e.g., through display 14 of FIG. 1) and a second antenna that conveys radio-frequency signals through therear face of device 10 (e.g., through rear housing wall 12R of FIG. 1 ).

FIG. 4 is a cross-sectional side view of electronic device 10 showinghow one or more antennas may be mounted within device 10 for conveying(radiating) radio-frequency signals through rear housing wall 12R. Asshown in FIG. 4 , display 14 may form the front face of device 10whereas rear housing wall 12R forms the rear face of device 10. In theexample of FIG. 4 , rear housing wall 12R is formed from a dielectricmaterial such as glass, sapphire, ceramic, or plastic. This is merelyillustrative and, if desired, rear housing wall 12R may also includeconductive portions (e.g., a conductive frame surrounding one or moredielectric windows in rear housing wall 12R, conductive cosmetic layers,etc.). Conductive housing sidewalls 12W may extend from the rear face tothe front face of device 10 (e.g., from rear housing wall 12R to display14).

Strap 16 may be secured to conductive housing sidewalls 12W usingcorresponding attachment structures 70. Attachment structures 70 mayinclude lugs, spring structures, clasp structures, adhesive structures,or any other desired attachment mechanisms. Strap 16 may be formed usingany desired materials (e.g., metal materials, dielectric materials, orcombinations of metal and dielectric materials). If desired, strap 16may be removed from attachment structures 70 (e.g., so that a user ofdevice 10 can swap in different straps having similar or differentmaterials).

Display 14 may include a display module 64 (sometimes referred to hereinas display stack 64, display assembly 64, or active area 64 of display14) and a display cover layer 62. Display module 64 may, for example,form an active area or portion of display 14 that displays images and/orreceives touch sensor input. The lateral portion of display 14 that doesnot include display module 64 (e.g., portions of display 14 formed fromdisplay cover layer 62 but without an underlying portion of displaymodule 64) may sometimes be referred to herein as the inactive area orportion of display 14 because this portion of display 14 does notdisplay images or gather touch sensor input.

Display module 64 may include conductive components (sometimes referredto herein as conductive display structures) that are used in formingportions of an antenna that radiates through the front face of device 10(e.g., an antenna having a radiating element such as a radiating slotelement defined by display module 64 and/or conductive housing sidewalls12W). The conductive display structures in display module 64 may, forexample, have planar shapes (e.g., planar rectangular shapes, planarcircular shapes, etc.) and may be formed from metal and/or otherconductive material that carries antenna currents for a front-facingantenna in device 10. The conductive display structures may include aframe for display module 64, pixel circuitry, touch sensor electrodes,an embedded near-field communications antenna, etc.

Display cover layer 62 may be formed from an optically transparentdielectric such as glass, sapphire, ceramic, or plastic. Display module64 may display images (e.g., emit image light) through display coverlayer 62 for view by a user and/or may gather touch or force sensorinputs through display cover layer 62. If desired, portions of displaycover layer 62 may be provided with opaque masking layers (e.g., inkmasking layers) and/or pigment to obscure the interior of device 10 fromview of a user.

Substrates such as substrate 66 (e.g., a rigid or flexible printedcircuit board, integrated circuit or chip, integrated circuit package,etc.) may be located within the interior of device 10. Substrate 66 maybe, for example, a main logic board (MLB) or other logic board fordevice 10. Other components such as components 68 (e.g., components usedin forming control circuitry 28 and/or input-output circuitry 20 of FIG.2 , battery 46, etc.) may be mounted to substrate 66 and/or elsewherewithin the interior of device 10.

As shown in FIG. 4 , a given (first) antenna 40-1 may be mounted withindevice 10 for radiating through rear housing wall 12R. Ground traces 67may be formed on substrate 66 and may form part of the antenna groundfor antenna 40-1. Conductive housing sidewalls 12W may also form part ofthe antenna ground for antenna 40-1 (e.g., ground traces 67 on substrate66 may be electrically shorted to conductive housing sidewalls 12W).Conductive portions of other components in device 10 may also form partof the antenna ground for antenna 40-1 (e.g., ground traces 67 onsubstrate 66, conductive housing sidewalls 12W, and/or conductiveportions of other components in device 10 may be held at a ground orreference potential).

Antenna 40-1 may include an antenna resonating element 82 formed fromconductive traces on a substrate such as substrate 84. Substrate 84 maybe a plastic substrate, a flexible printed circuit substrate, a rigidprinted circuit substrate, a ceramic substrate, or any other desireddielectric substrate. The conductive traces in antenna resonatingelement 82 (sometimes referred to herein as antenna radiating element82, resonating element 82, radiating element 82, or antenna element 82)may, for example, be patterned onto substrate 84 using a laser directstructuring (LDS) process. In another suitable arrangement, antennaresonating element 82 may be formed from metal foil, layers of sheetmetal, conductive portions of the housing for device 10, etc.

Antenna resonating element 82 may be a patch antenna resonating element,an inverted-F antenna resonating element, a planar inverted-F antennaresonating element, a monopole resonating element, a dipole resonatingelement, a loop resonating element, another type of antenna resonatingelement, and/or a combination of these types of antenna resonatingelements. If desired, antenna resonating element 82 and/or substrate 84may laterally extend circumferentially around central axis 94 (e.g.,antenna resonating element 82 may lie within a given plane or surfaceand may have a loop shape that extends around an opening, where centralaxis 94 runs orthogonally through the opening). Positive antenna feedterminal 58 for antenna 40-1 may be coupled to antenna resonatingelement 82. The ground antenna feed terminal for antenna 40-1 (not shownin FIG. 4 for the sake of clarity) may be coupled to conductive housingsidewalls 12W, ground traces 67 on substrate 66, or any other desiredportion of the antenna ground for antenna 40-1.

Rear housing wall 12R may extend across substantially all of the lengthand width of device 10 (e.g., in the X-Y plane). Rear housing wall 12Rmay be optically opaque or optically transparent or may include bothoptically opaque and optically transparent portions (e.g., rear housingwall 12R may include optically transparent windows in an otherwiseoptically opaque member). Antenna resonating element 82 may overlap rearhousing wall 12R and may, if desired, be spaced apart from rear housingwall 12R, pressed against rear housing wall 12R, adhered to rear housingwall 12R, etc. In this way, antenna 40-1 may be formed at or adjacent tothe rear face of device 10 for radiating through rear housing wall 12R.If desired, antenna resonating element 82 may conform to the shape ofthe interior surface of rear housing wall 12R (e.g., antenna resonatingelement 82 need not be planar). In the example of FIG. 4 , the interiorsurface of rear housing wall 12R has a slightly curved or concave shape(e.g., to form a protruding portion 72 that increases the total volumefor components within device 10 relative to scenarios where the interiorsurface of rear housing wall 12R is flat).

Antenna 40-1 may transmit and receive radio-frequency signals (e.g., inat least the cellular low band, the cellular low-midband, the cellularmidband, and/or the cellular high band) through rear housing wall 12R.The radio-frequency signals transmitted by antenna 40-1 may be shieldedfrom electrical components 68 and the antenna at the front face ofdevice 10 by ground traces 67 on substrate 66, for example. Similarly,ground traces 67 and substrate 66 may shield antenna 40-1 fromcomponents 68 and the antenna at the front face of device 10, therebymaximizing isolation between the antennas in device 10 despite therelatively small size of device 10.

By forming antenna 40-1 at rear housing wall 12R, the vertical height ofdevice 10 (e.g., parallel to the Z-axis of FIG. 4 ) may be shorter thanwould otherwise be possible in scenarios where the corresponding antennaresonating element is located elsewhere on device 10 (while stillallowing antenna 40-1 to exhibit satisfactory antenna efficiency). As anexample, the vertical height of device 10 may be less than or equal to11.4 mm, less than 15 mm, between 8 and 11.4 mm, or any other desiredheight while still allowing antenna 40-1 to operate with satisfactoryantenna efficiency.

In practice, the wireless performance of antenna 40-1 may be optimizedby the presence of an external object adjacent to rear housing wall 12R.For example, the presence of the user's wrist 80 adjacent to rearhousing wall 12R when the user is wearing device 10 may enhance thewireless performance of antenna 40-1. During operation, antenna 40-1 maytransmit and/or receive radio-frequency signals having electric fields(E) that are oriented normal to the surfaces of rear housing wall 12Rand wrist 80. These signals may sometimes be referred to as surfacewaves, which are then propagated along the surface of wrist 80 andoutwards, as shown by paths 76 (e.g., antenna resonating element 82 andwrist 80 may serve as a waveguide that directs the surface wavesoutwards). This may allow the radio-frequency signals conveyed byantenna 40-1 to be properly received by external communicationsequipment (e.g., a wireless base station) even though antenna 40-1 islocated close to wrist 80 and typically pointed away from the externalcommunications equipment.

Coil structures 44 may also be mounted within device 10 at or adjacentto rear housing wall 12R. Coil structures 44 may be spaced apart fromrear housing wall 12R, pressed against rear housing wall 12R, adhered torear housing wall 12R, etc. As shown in FIG. 4 , antenna 40-1 (e.g.,antenna resonating element 82) may laterally extend around (surround)coil structures 44 (e.g., coil structures 44 may lie within an openingin antenna resonating element 82). Coil structures 44 may alsocircumferentially surround central axis 94 (e.g., coil structures 44 maylaterally extend around central axis 94 within the X-Y plane or anothersurface). In this way, coil structures 44 and antenna 40-1 may extendconcentrically around central axis 94. Coil structures 44 may laterallysurround module 88 and/or an opening that overlaps module 88.

Coil structures 44 may receive wireless charging signals through rearhousing wall 12R (e.g., when device 10 is placed on a wireless poweradapter or other wireless power transmitting device). The wirelesscharging signals may induce currents on coil structures 44 that are usedby wireless power receiver circuitry 42 for charging battery 46 (FIG. 2). Coil structures 44 may include a single conductive coil (e.g., aninductive coil) or more than one conductive coil. In one suitablearrangement, coil structures 44 may include a first coil with windingsthat coil (wind) around central axis 94 and a second coil with windingsthat extend perpendicular to the windings in the first coil. The secondcoil may, for example, include windings that coil (wind) around axis 94(e.g., a ring-shaped axis that loops around central axis 94 and lieswithin the X-Y plane). The windings in the first and second coils mayinclude conductive wire (e.g., copper wire), conductive traces, or anyother desired conductive material.

Coil structures 44 may include ferrite structures such as ferritestructures 86. Ferrite structures 86 may include ferrite shieldstructures that help to electromagnetically shield coil structures 44from other components in device 10. If desired, ferrite structures 86may be omitted for one or more portions of coil structures 44. Ifdesired, ferrite structures 86 may additionally or alternatively includeone or more ferrite cores for the windings in coil structures 44 (e.g.,the windings in coil structures 44 may be wound around the ferritecore(s)). Ferrite cores in coil structures 44 may help to maximize thewireless charging efficiency for device 10.

Device 10 may include module 88 (sometimes referred to as backsidecircuitry module 88 or backside control module 88) that is mounted on oradjacent to rear housing wall 12R. Backside circuitry module 88 mayinclude sensor circuitry and may therefore sometimes be referred toherein as sensor module 88. Central axis 94 may extend (e.g.,orthogonally) through a lateral surface of backside circuitry module 88.Backside circuitry module 88 may be separated from rear housing wall12R, pressed against rear housing wall 12R, adhered to rear housing wall12R, etc. Backside circuitry module 88 may overlap protruding portion 72of rear housing wall 12R and may be partially or completely locatedwithin protruding portion 72 (e.g., defined between the portions of rearhousing wall 12R between dashed lines in FIG. 4 ). Backside circuitrymodule 88 may include a rigid printed circuit board, flexible printedcircuit, integrated circuit chip, integrated circuit package, plasticsubstrate, or other substrates for supporting one or more sensors 92(e.g., one or more sensors 92 may be mounted to a sensor board or asupport structure). Sensors 92 may, for example, include sensors ininput-output devices 22 of FIG. 2 .

If desired, some sensor electrodes may be formed, within, at, or on rearhousing wall 12R (e.g., the sensor electrodes may be at least partiallyembedded within the dielectric material of rear housing wall 12R). Inthis example, the sensor electrodes may be coupled to sensor circuitryin backside circuitry module 88 using one or more conductive paths (notshown in FIG. 4 for the sake of clarity). The sensor electrodes may, forexample, be electrocardiogram (ECG or EKG) electrodes. Sensor circuitryin backside circuitry module 88 may sense the electrical activity of auser's heart using the sensor electrodes formed within, at, or on rearhousing wall 12R while the user wears device 10, for example. In anothersuitable arrangement, the sensor electrodes may be mounted withinbackside circuitry module 88.

Backside circuitry module 88 may include ground traces (e.g., groundtraces in a printed circuit board for sensor circuitry) that are held ata ground or reference potential. If desired, the ground traces inbackside circuitry module 88 may be shorted to conductive housingsidewalls 12W, ground traces 67, or other ground structures in device10. Printed circuit 91 such as a flexible printed circuit may connect tosubstrate 66 (using connector 78) and may connect to backside circuitrymodule 88 (using connector 90). As an example, backside circuitry module88 may convey sensor signals or other signals to components on substrate66 (e.g., components 68 such as control circuitry 28 in FIG. 2 ) viaprinted circuit 91 and may receive control signals or other signals fromthe components on substrate 66. If desired, circuitry other than sensorcircuitry in backside circuitry module 88 may also convey and receivedata signals or other signals to and from the components on substrate66.

In some applications, it may be desirable to incorporate circuitry forhigh data rate wireless communication connections or links (e.g.,implemented using wireless circuitry 34 in FIG. 2 ) to device 10,thereby improving the data transfer capabilities of device 10. As anexample, these wireless connections, in place of bulky ports orconnectors for wired connections, may be useable for conveying debugdata, test data, and/or other data. If desired, these wirelesscommunication connections may transmit and/or receive data using highdata rates in a bidirectional data link (or unidirectional data link) inthe near-field domain (e.g., across a distance of less than five inches,less than four inches, less than three inches, etc., rather than in afar-field domain across a distance of greater than five inches, greaterthan four inches, etc.). As examples, the wireless connections maytransmit and receive data using high data rate data transfer operationsat speeds of 1 Kilobit (Kbps) per second or more, 100 Kbps or more, 1Megabit per second (Mbps) or more, 100 Mbps or more, 500 Mbps or more, 1Gigabit bit per second or more, etc. to satisfactorily perform wirelessdata transfer operations (e.g., for conveying debug, test, and/or otherdata).

Given the limited device interior space, incorporating additionalwireless circuitry (e.g., antennas) to implement these wirelessconnections for data transfer may require compact and well-integratedantenna elements. Still referring to FIG. 4 , device 10 may includeantennas 40-2 or 40-3 used to implement the additional wirelesscircuitry for high data rate, bidirectional, and/or near-field wirelessconnections for data transfer. In the illustrative examples describedherein, device 10 may include either antenna 40-2 or antenna 40-3. Thisis merely illustrative. If desired, device 10 may include both antennas40-2 and 40-3 as illustrated in FIG. 4 .

As shown in FIG. 4 , antenna 40-2, related components for antenna 40-2,and/or other antenna elements may be formed from and/or integrated withcomponents within backside circuitry module 88. By integrating antennaelements for antenna 40-2 within backside circuitry module 88, device 10may implement additional wireless connections in a compact andwell-integrated manner. In some configurations, the additional wirelesscircuitry within backside circuitry module 88 may be configured totransmit and receive debug data, test data, and/or other data using highdata rate, bidirectional, and/or near-field wireless communicationlinks.

As an example, antenna 40-2 may include one or more sets of antennastructures (sometimes referred to herein as antenna elements) formedfrom metal layers embedded within a substrate in backside circuitrymodule 88. The substrate may be a printed circuit or a logic board fordevice 10 such as a sensor logic board. The substrate may havecomponents such as transceiver circuitry, integrated circuit packages,and other components, which are mounted to a top surface of thesubstrate that opposes a bottom surface of the substrate at which theone or more separate antenna structures (e.g., antenna resonatingelements) formed.

As another example, antenna 40-2 may include one or more sets of antennastructures formed from conductive traces on support structures forcomponents within backside circuitry module 88. The support structuresmay support sensor components such as sensors 92 and/or other sensorcircuitry within backside circuitry module 88, may support a printedcircuit or logic board within backside circuitry module 88, may supportother components within backside circuitry module 88, and/or may mountedcomponents within backside circuitry module 88 to rear housing wall 12R.

These antenna structures for antenna 40-2 (e.g., antenna structuresembedded within a substrate in backside module 88 and/or formed onsupport structures in backside circuitry module 88) may include antennaresonating elements, parasitic antenna elements, antenna groundstructures, antenna feed terminals, antenna short circuit paths,radio-frequency transmission line structures, antenna tuning components,and/or any other suitable antenna elements. In particular, the antennaresonating elements for antenna 40-2 may include patch antennaresonating elements, inverted-F antenna resonating elements, planarinverted-F antenna resonating elements, monopole resonating elements,dipole resonating elements, loop resonating elements, another type ofantenna resonating element, and/or a combination of these types ofantenna resonating elements.

In the example of FIG. 4 , two separate antenna structures (e.g., twoseparate antenna resonating elements embedded within a substrate inbackside module 88 or formed on support structures in backside circuitrymodule 88) for antenna 40-2 may be formed on opposing lateral sides ofbackside circuitry module 88 such as at locations 101-1 and 101-2.Antenna structures formed at location 101-1 may transmit and receiveradio-frequency signals through an antenna aperture or opening (at leastpartly defined by coil structures 44 and a portion of backside circuitrymodule 88) and through rear housing wall 12R as indicated by arrow102-1. Antenna structures formed at location 101-2 may transmit andreceive radio-frequency signals through an additional antenna apertureor opening (at least partly defined by coil structures 44 and a portionof backside circuitry module 88) and through rear housing wall 12R asindicated by arrow 102-2.

If desired, additional antenna structures (e.g., one, two, three, four,five, six, more than six, etc., separate antenna resonating elements inaddition to antenna structures at locations 103-1 and 103-2) for antenna40-2 may be formed within backside circuitry module 88. In the exampleof backside circuitry module 88 having peripheral edges extendingcircumferentially around central axis 94, the additional separateantenna structures (and the antenna structures at locations 101-1 and101-2) for antenna 40-2 may be formed in pairs at opposing peripheral(e.g., lateral) edges of backside circuitry module 88. If desired, theantenna structures for antenna 40-2 may be formed at any suitablelocation within backside circuitry module 88.

The configuration of antenna structures for wireless circuitry in device10 operable to perform high data rate data transfer operations throughrear housing wall 12R as described in connection with antenna 40-2 ismerely illustrative. If desired, wireless circuitry associated device 10may be implemented outside of backside circuitry module 88. In theexample of FIG. 4 , device 10 may include antenna 40-3 (instead ofantenna 40-2, or if desired, in addition to antenna 40-2). Antennastructures (sometimes referred to herein as antenna elements) forantenna 40-3 may be formed at substrate 66 (e.g., from conductive traceson a bottom surface of substrate 66 that opposes a top surface ofsubstrate 66 at which components 68 are mounted, from metal layersembedded within substrate 66, from conductive traces on structures thatextends from substrate 66, etc.).

These antenna structures for antenna 40-3 (e.g., formed at substrate 66)may include antenna resonating elements, parasitic antenna elements,antenna ground structures, antenna feed terminals, antenna short circuitpaths, radio-frequency transmission line structures, antenna tuningcomponents, and/or any other suitable antenna elements. In particular,the antenna resonating elements for antenna 40-3 may include patchantenna resonating elements, inverted-F antenna resonating elements,planar inverted-F antenna resonating elements, monopole resonatingelements, dipole resonating elements, loop resonating elements, anothertype of antenna resonating element, and/or a combination of these typesof antenna resonating elements.

In the example of FIG. 4 , two separate antenna structures (e.g., twoseparate antenna resonating elements) for antenna 40-3 may be formed onopposing lateral sides of substrate 66 such as at location 103-1 and103-2. Antenna structures formed at location 103-1 may transmit andreceive radio-frequency signals through an antenna aperture or opening(at least partly defined by housing sidewall 12W, antenna resonatingelement 82, and substrate 84) and through rear housing wall 12R asindicated by arrow 104-1. Antenna structures formed at location 103-2may transmit and receive radio-frequency signals through an additionalantenna aperture or opening (at least partly defined by housing sidewall12W, antenna resonating element 82, and substrate 84) and through rearhousing wall 12R as indicated by arrow 104-2.

If desired, additional antenna structures (e.g., one, two, three, four,five, six, more than six, etc., separate antenna resonating elements inaddition to antenna structures at locations 103-1 and 103-2) for antenna40-3 may be formed at substrate 66. In some configurations, substrate 66may have peripheral edges that oppose sidewalls 12W and that surroundcentral axis 94. In these configurations, the additional separateantenna structures (and the antenna structures at locations 103-1 and103-2) for antenna 40-3 may be formed in pairs at or near opposingperipheral edges of substrate 66 (e.g., on the same bottom surface ofsubstrate 66 on opposing sides of substrate 66).

Radio-frequency transceiver circuitry for antenna 40-2 and/orradio-frequency transceiver circuitry for antenna 40-3 may be formed asone or more of the components 68 such as an integrated circuit packageon substrate 66, formed as one or more components in backside circuitrymodule 88, and/or formed at any suitable location in device 10.Respective radio-frequency transceiver circuitries for antennas 40-2 and40-3 may be coupled to corresponding antenna feeds for antennas 40-2 and40-3 via radio-frequency transmission lines. The radio-frequencytransmission line may convey radio-frequency signals between therespective radio-frequency transceiver circuitry and the correspondingantenna structures.

The radio-frequency transceiver circuitries for antennas 40-2 and 40-3may include any desired type of transceiver circuitry such as GPSreceiver circuitry, WLAN/WPAN transceiver circuitry, cellular telephonetransceiver circuitry, near-field communications transceiver circuitry,centimeter and millimeter wave transceiver circuitry, etc. As anexample, the radio-frequency transceiver circuitries for antennas 40-2and 40-3 may implement near-field communications transceiver circuitry38 (FIG. 2 ) operable at about 60 GHz (or at any othermillimeter/centimeter wave frequency or other suitable frequencies) ormay implement any other types of centimeter and millimeter wavetransceiver circuitry. The radio-frequency transceiver circuitries mayuse corresponding antenna structures for antennas 40-2 and 40-3 totransmit and receive debug data, test data, and/or other data based on ahigh data rate, bidirectional, and/or near-field wireless link fortwo-way data transfer operations.

If desired, the radio-frequency transceiver circuitries respectivelycoupled to antennas 40-2 and 40-3 may implement a half-duplex system byusing pairs of antenna structures in the corresponding antenna tosimultaneously receive or simultaneously transmit radio-frequencyantenna signals. As an example, the half-duplex system may use both ofantenna structures at locations 101-1 and 101-2 to simultaneouslyreceive large amounts of data (e.g., software, firmware, test data,debug data, etc.), and may thereafter use both of antenna structures atlocations 101-1 and 101-2 to transmit large amounts of data (e.g.,acknowledgement data, test data such as test results, etc.). If desired,the radio-frequency transceiver circuitries respectively coupled toantennas 40-2 and 40-3 may implement a full-duplex system by using oneof a pair of antenna structures in the corresponding antenna tocontinually serve a transmit function and by using the other one of thepair of antenna structures in the corresponding antenna to continuallyserve a receive function. As an example, the full-duplex system may useantenna structure at location 103-1 to receive data such as software,firmware, test data, debug data from a transmitting device andsimultaneously interact with the transmitting device by using antennastructures at location 103-2 to transmit data (e.g., test results,response or acknowledgement data) back to the transmitting device.

These examples are merely illustrative. If desired, antenna structuresat locations 101-1 and 101-2 may be used in a full-duplex system. Ifdesired, antennas structures at locations 103-1 and 103-2 may be used ina half-duplex system.

These configurations of the additional wireless circuitry in device 10(e.g., antennas 40-2 and 40-3) are merely illustrative. If desired,wireless circuitry for near-field data transfer (through rear housingwall 12R) may be implemented in any suitable region of device 10 (e.g.,at components of device 10 besides substrate 66 and backside controlmodule 88, at components near and/or overlapping the rear housing wall12R, etc.). If desired, the wireless circuitry for near-field datatransfer may include one or more antenna resonating elements instead ofthe antenna resonating elements for antennas 40-2 and 40-3 in FIG. 4 .

FIG. 5 is a diagram showing an illustrative dipole antenna resonatingelement that may be used to implement antenna structures such as antennaelements in antennas 40-2 and/or 40-3 in FIG. 4 . As shown in FIG. 5 ,antenna 40 (referring to one or more of antennas 40-2, 40-3, and/orother antennas in device 10) may be implemented as a dipole antenna.Antenna 40 may include a dipole antenna element (sometimes referred toas a dipole element or a dipole antenna resonating element) havingconductive (resonating or radiating) elements (arms) 110-1 and 110-2that extend along the same axis but in opposite directions from antennafeed 116. Antenna feed 116 may include ground antenna feed terminal 112coupled to conductive element 110-1 and positive antenna feed terminal114 coupled to conductive element 110-2.

Radio-frequency transmission line 118 may have a positive signal pathcoupled to positive antenna feed terminal 114 and a ground signal pathcoupled to ground antenna feed terminal 112. Balun 120 may be interposedalong radio-frequency transmission line 118 and may be interposedbetween a portion of radio-frequency transmission line 118 and antennafeed 116. If desired, balun 120 may be provided in any suitableconfiguration within antenna 40 to provide conversion functionalitiesbetween balanced and unbalanced signals between the dipole antennaelement (e.g., conductive elements 110-1 and 110-2) and radio-frequencytransmission line 118.

In general, the frequency response of an antenna is related to the sizesand shapes of the conductive structures in the antenna. Dipole antennasof the type shown in FIG. 4 tend to exhibit response peaks when thelength of the dipole antenna element (e.g., the combined length ofconductive structures 110-1 and 110-2, e.g., length D1) is equal to theeffective wavelength of operation of antenna 40 divided by two. Theeffective wavelength of operation may be equal to a freespace wavelengthmultiplied by a constant value that is determined by the dielectricmaterials around the dipole antenna element.

Conductive elements 110-1 and 110-2 may be backed by an antenna groundor a ground plane such as antenna ground 108, which may serve as anantenna reflector and is sometimes referred to herein as antennareflector 108. In other words, conductive elements 110-1 and 110-2 mayextend above a plane in which antenna reflector 108 is formed.Conductive elements 110-1 and 110-2 may be disposed a distance D2 awayfrom antenna reflector 108. Distance D2 may be equal to the effectivewavelength of operation of antenna 40 divided by four or may be anyother suitable distance.

In some configurations, the dipole antenna elements for antenna 40(e.g., conductive elements 110-1 and 110-2, radio-frequency transmissionlines 118, antenna reflector 108, balun 120, etc.) may be formed frommetal layers (separated by dielectric layers) and vias or otherstructures embedded in a substrate. As examples, antenna reflector 108may be formed from connected via structures in a substrate,radio-frequency transmission lines 118 may be formed from striplinestructures implemented as metal layers, and conductive elements 110-1and 110-2 may be formed from metal layers formed on the substrate. Ifdesired, other configurations maybe used to implement the dipoleelements for antenna 40. The example of FIG. 5 is merely illustrative.In general, the dipole antenna element may have any desired shape orsize, may be formed with or without a reflector structure (e.g., antennareflector 108), may have additional elements, may be formed using anysuitable structures, etc.

As an example, antenna structures at locations 101-1 and 101-2 forantennas 40-2 (similarly antenna structures at locations 103-1 and 103-2for 40-3) may each be formed from a dipole antenna element of the typeshown in FIG. 5 . As another example, only some of antenna structuresfor antennas 40-2 and/or 40-3 may be formed from a dipole antennaelement of the type shown in FIG. 5 and the remaining separate sets ofthe antenna structures may be implemented using any other suitable typesof antenna elements. If desired, any other suitable types of antennaresonating elements may be used to implement one or more (or all) of theantenna structures for antennas 40-2 and/or 40-3.

Electronic device 10 may use antennas 40 (e.g., antennas 40-2 and/orantenna 40-3) to transmit and receive radio-frequency signals to andfrom another electronic device to perform near-field high data rate datatransfer operations through rear housing wall 12R. FIG. 6 is a diagramof a first electronic device such as device 10 and a second electronicdevice such as device 130 operable to transmit and receiveradio-frequency signals to and from each other to perform the high datarate data transfer operations.

Electronic device 130 may be a computing device such as a laptopcomputer, a computer monitor containing an embedded computer, a tabletcomputer, a cellular telephone, a media player, or other handheld orportable electronic device, a smaller device such as a wristwatchdevice, a pendant device, a headphone or earpiece device, a deviceembedded in eyeglasses or other equipment worn on a user's head, orother wearable or miniature device, a television, a computer displaythat does not contain an embedded computer, a gaming device, anavigation device, an accessory that support the functions of one ormore of these devices, a charging device or charging equipment or othertypes of electronic equipment that interfaces with one or more of thesedevices, an embedded system such as a system in which electronicequipment with a display is mounted in a kiosk or automobile, equipmentthat implements the functionality of two or more of these devices, orother electronic equipment.

As an illustrative example, device 130 may be sometimes referred toherein as charging equipment or a charging device such as a wirelesspower transmitting device, whereas device 10 may be sometimes referredto herein as a wireless power receiving device (e.g., a wristwatch thatreceives wireless power from charging equipment). Other configurationsmay be used for devices 10 and 130 if desired. As another illustrativeexample, device 130 may be a debug or test device (equipment) configuredto perform diagnostic operations on device 10, test functions of device10, perform (software) updates on device 10, etc.

In the example where device 130 is a wireless power transmitting device,device 130 may include one or more coils that are used in transmittingwireless power to device 10. During operation, control circuitry 132 mayuse wireless power transmitting circuitry in device 130 and one or morecoils coupled to the wireless power transmitting circuitry to transmitalternating current electromagnetic signals to device 10 and therebyconvey wireless power to wireless power receiving circuitry 42 in device10 (FIG. 2 ). The wireless power transmitting circuitry may haveswitching circuitry (e.g., transistors) that are turned on and off basedon control signals provided by control circuitry 132 to create ACcurrent signals through the one or more coils. As the AC currents passthrough the coils, alternating-current electromagnetic fields (wirelesspower signals) are produced that are received by corresponding coilstructures 44 coupled to wireless power receiving circuitry 42 inreceiving device 10 (FIG. 2 ). When the alternating-currentelectromagnetic fields are received by coil structures 44, correspondingalternating-current currents and voltages are induced in coil structures44. Rectifier circuitry in wireless power receiving circuitry 42 mayconvert received AC signals (received alternating-current currents andvoltages associated with wireless power signals) from coil structures 44into DC voltage signals for powering device 10. The DC voltages may beused in powering components in device 10 such as a display, touch sensorcomponents and other sensors (e.g., accelerometers, force sensors,temperature sensors, light sensors, pressure sensors, gas sensors,moisture sensors, magnetic sensors, etc.), wireless communicationscircuitry 34 for communicating wirelessly with other devices orequipment, audio components, and other components, and may be used incharging an internal battery in device 10 such as battery 46 (FIG. 2 ).

Device 130 may include control circuitry 132 having storage circuitry.The storage circuitry may include hard disk drive storage, nonvolatilememory (e.g., flash memory or other electrically-programmable-read-onlymemory configured to form a solid-state drive), volatile memory (e.g.,static or dynamic random-access-memory), etc. Control circuitry 132 mayinclude processing circuitry. The processing circuitry may be used tocontrol the operation of device 130. The processing circuitry mayinclude on one or more microprocessors, microcontrollers, digital signalprocessors, host processors, baseband processor integrated circuits,application specific integrated circuits, central processing units(CPUs), etc. Control circuitry 132 may be configured to performoperations in device 130 using hardware (e.g., dedicated hardware orcircuitry), firmware, and/or software. Software code for performingoperations in device 130 may be stored on storage circuitry in controlcircuitry 132 (e.g., the storage circuitry may include non-transitory(tangible) computer readable storage media that stores the softwarecode). The software code stored on the storage circuitry in controlcircuitry 132 may be executed by the processing circuitry in controlcircuitry 132.

In the wireless power transmitting device example, control circuitry 132may be used in determining power transmission levels, processing sensordata, processing user input, processing other information such asinformation on wireless coupling efficiency from wireless powertransmitting circuitry, processing information from wireless powerreceiving circuitry, processing information to determine when to startand stop wireless charging operations, adjusting charging parameterssuch as charging frequencies, coil assignments in a multi-coil array,and wireless power transmission levels, and performing other controlfunctions.

To support interactions with external device or equipment, controlcircuitry 132 may be used in implementing communications protocols.Communications protocols that may be implemented using control circuitry28 include internet protocols, wireless local area network protocols(e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocolsfor other short-range wireless communications links such as theBluetooth® protocol or other wireless personal area network (WPAN)protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMOprotocols, antenna diversity protocols, satellite navigation systemprotocols (e.g., global positioning system (GPS) protocols, globalnavigation satellite system (GLONASS) protocols, etc.), IEEE 802.15.4ultra-wideband communications protocols or other ultra-widebandcommunications protocols, data transfer protocols, etc. Eachcommunications protocol may be associated with a corresponding radioaccess technology (RAT) that specifies the physical connectionmethodology used in implementing the protocol.

Control circuitry 132 may handle data transfer protocols to perform highdata rate data transfer operations (e.g., data transfer operations atspeeds of 100 Megabits per second (Mbps) or more, at 500 Mbps or more, 1bit per second or more, etc.). Data transfer protocols that may beimplemented by control circuitry 132 may include Universal Serial Bus(USB) protocols, universal asynchronous receiver/transmitter (UART)protocols, Peripheral Component Interconnect (PCI) protocols, PeripheralComponent Interconnect Express (PCIe) protocols, Accelerated GraphicsPort (AGP) protocols, or any other desired data transfer protocolscapable of data speeds (i.e., data rates) of greater than or equal toapproximately 100 Mbps.

Electronic device 130 of FIG. 6 may be provided with wireless circuitry134. Wireless circuitry 134 may be used to support wirelesscommunications in multiple wireless communications bands. Communicationsbands handled by wireless circuitry 130 can include satellite navigationsystem communications bands, cellular telephone communications bands,wireless local area network communications bands, wireless personal areanetwork communications bands, near-field communications bands,ultra-wideband communications bands, centimeter wave communicationsbands, millimeter wave communications bands, or other wirelesscommunications bands.

Wireless circuitry 130 may include one or more antennas 138. Antennas138 may include loop antennas, inverted-F antennas, strip antennas,planar inverted-F antennas, patch antennas, slot antennas, monopoleantennas, dipole antennas, hybrid antennas that include antennastructures of more than one type, or other suitable antennas. Ifdesired, one or more antennas 138 may be provided with circuitry such asfilter circuitry (e.g., one or more passive filters and/or one or moretunable filter circuits). Discrete components such as capacitors,inductors, and resistors may be incorporated into the filter circuitry.Capacitive structures, inductive structures, and resistive structuresmay also be formed from patterned metal structures (e.g., part of anantenna). If desired, antennas 138 may be provided with adjustablecircuits such as tunable components that tune the antenna overcommunications (frequency) bands of interest. The tunable components maybe part of a tunable filter or tunable impedance matching network, maybe part of an antenna resonating element, may span a gap between anantenna resonating element and antenna ground, etc.

Wireless circuitry 134 may include one or more radio-frequencytransceiver circuitries 136 (e.g., near-field communications transceivercircuitry, centimeter wave and millimeter wave transceiver circuitry, orother types of transceiver circuitry) each coupled to at least a givenantenna 138 using a radio-frequency transmission line path. Theradio-frequency transmission line path may include a positive signalconductor and a ground signal conductor. A matching network may includecomponents such as inductors, resistors, and capacitors used in matchingthe impedance of antenna 138 to the impedance of the radio-frequencytransmission line path. The radio-frequency transmission line path maybe coupled to antenna feed structures associated with one or moreantennas 138. A positive antenna feed terminal may be coupled to anantenna resonating (radiating) element within a given antenna 138. Aground antenna feed terminal may be coupled to an antenna ground in agiven antenna 138. The signal conductor may be coupled to the positiveantenna feed terminal and the ground conductor may be coupled to theground antenna feed terminal.

In some configurations that are sometimes described herein as anexample, radio-frequency transceiver circuitry 136 may includenear-field communications circuitry operable at frequencies above about10 GHz (e.g., at frequencies between about 10 GHz and 300 GHz), and issometimes referred to herein as millimeter/centimeter wave transceivercircuitry. The millimeter/centimeter wave transceiver circuitry maysupport communications in Extremely High Frequency (EHF) or millimeterwave communications bands between about 30 GHz and 300 GHz and/or incentimeter wave communications bands between about 10 GHz and 30 GHz. Asan example, the near-field communications circuitry may includemillimeter/centimeter wave transceiver circuitry operable at about 60GHz (or any frequency in a millimeter/centimeter wave frequency band) toestablish a wireless link useable for data transfer operations (e.g.,with device 10 as a wristwatch or as another type of electronic deviceor equipment). If desired, the near-field communications circuitry mayinclude radio-frequency transceiver circuitry operable at a frequencylower than 10 GHz to establish a wireless link usable for data transfer.In some configurations, non-near-field communications circuitry may beused to support communications in Extremely High Frequency (EHF) ormillimeter wave communications bands between about 30 GHz and 300 GHzand/or in centimeter wave communications bands between about 10 GHz and30 GHz. Wireless data transfer protocols may be used by transceivercircuitry 136 to bidirectionally transfer data at these frequencies.

If desired, wireless circuitry 134 in device 130 may transmit and/orreceive data using high data rates in a bidirectional data link (orunidirectional data link) and in the near-field domain (e.g., across adistance of less than five inches, less than four inches, less thanthree inches, etc., rather than in a far-field domain across a distanceof greater than five inches, greater than four inches, etc.) to and/orfrom wireless circuitry 34 in device 10 (via signals 140). As examples,the wireless connections may transmit and receive data using high datarate data transfer operations at speeds of 1 Kilobit (Kbps) per secondor more, 100 Kbps or more, 1 Megabit per second (Mbps) or more, 100 Mbpsor more, 500 Mbps or more, 1 Gigabit bit per second or more, etc. tosatisfactorily perform wireless data transfer operations (e.g., forconveying debug, test, and/or other data).

Communications between the respective wireless circuitries for devices10 and 130 at relatively high frequencies, such as at frequencies ofabout 10-300 GHz, and in the near-field domain (while being helpful ineffectively facilitating high data rate data transfer operations) canface significant challenges if care is not taken. As an example, signalpolarization misalignment between signals from respective wirelesscircuitries for devices 10 and 130 and directional misalignment betweenthe respective wireless circuitries for devices 10 and 130 can oftendegrade wireless communication links at these relatively highfrequencies and in the near-field domain. It is therefore desirable toprovide mechanisms through which devices 10 and 130 (e.g., respectivewireless circuitries in devices 10 and 130) may be more robustly andreliably aligned with respect to each other to satisfactorily establishand maintain these wireless communication links.

FIGS. 7 and 8 show how a first device such as device 10 and a seconddevice such as device 130 may be configured to align and attach to eachother in a robust manner to satisfactorily establish and maintain thesewireless communication links. FIG. 7 is a bottom-up view of anillustrative electronic device such as device 10 (in FIG. 6 ) havingalignment or attachment structures configured to align device 10 withand attach device 10 to other devices such as device 130 (in FIG. 6 ).As shown in FIG. 7 , rear housing wall 12R may define a rear face ofdevice 10. Rear housing wall 12R may have a circular protruding portionwithin dashed circle 72. In other words, the portion of rear housingwall 12R outside of dashed circle 72 may lie substantially on a flatplane (e.g., the plane of the page, the X-Y plane), and the portion ofrear housing wall 12R inside of dashed circle 72 may protrude from theplane in the −Z direction (e.g., out of the page in FIG. 7 ).

Components in device 10 such as backside circuitry module 88 and one ormore coils 96 may overlap the protruding portion in rear housing wall12R. Sensor electrodes 150 may also be formed at a protruding portion ofrear housing wall 12R. In particular, sensor electrodes 150 may have twoportions that laterally surround backside circuitry module 88 and one ormore coils 96. Additionally, one or more coils 96 may surround backsidecircuitry module 88.

In some examples (e.g., configurations without antenna 40-3), device 10may include antenna 40-2 with antenna resonating elements 154-1 and154-2 (e.g., antenna structures formed at locations 101-1 and 101-2 inFIG. 4 ). Antenna resonating elements 154-1 and 154-2 may be formed onopposing sides of backside circuitry module 88 and may be integratedwithin components of backside circuitry module 88. In particular,antenna resonating element 154-1 may be interposed between a portion ofcoil(s) 96 and a portion of backside circuitry module 88. Antennaresonating element 154-2 may be interposed between a different portionof coil(s) 96 and a different portion of backside circuitry module 88.As shown in FIG. 7 , antenna resonating elements 154-1 and 154-2 may beformed on top and bottom sides of backside circuitry module 88 parallelto the top and bottom sidewalls 12W in which attachment structures 70are formed. In other words, antenna resonating element 154-1 may beinterposed between the top sidewall 12W and a portion of backsidecircuitry module 88, and antenna resonating element 154-1 may beinterposed between the bottom sidewall 12W and a portion of backsidecircuitry module 88. This is merely illustrative. If desired, antennaresonating elements 154-1 and 154-2 may be formed at any suitablelocation in device 10 (e.g., on left and right sides of backsidecircuitry module 88). If desired, additional resonating elements(additional to antenna resonating elements 154-1 and 154-2) may be format any suitable location in device 10.

In some examples (e.g., configurations without antenna 40-2), device 10may include antenna 40-3 with antenna resonating elements 156-1 and156-3 (e.g., antenna structures formed at locations 130-1 and 130-2 inFIG. 4 ) and optionally antenna resonating elements 156-2 and 156-4instead of or in addition to antenna resonating elements 156-1 and156-3. Antenna resonating elements 156-1, 156-2, 156-3, and 156-4 may bedisposed along the four sides of rear housing wall 12R and outside theprotruding portion of rear housing wall 12R. Antenna resonating elements156-1, 156-2, 156-3, and 156-4 may be formed at substrate 66 (FIG. 3 )and may be aligned with openings in antenna resonating element 82 (notshown in FIG. 4 for clarity), which may overlap a substantial part ofthe portion of rear housing wall 12R outside of dashed circle 12R.

These examples are merely illustrative. If desired, any of antennaresonating elements 156 may be omitted from antenna 40-3 and any ofantenna resonating elements 154 may be omitted from antenna 40-2. Ifdesired, any other antenna elements at any suitable locations may beincorporated into device 10 as part of antennas 40-2 or 40-3.

To ensure that antennas 40-2 and/or 40-3 may effectively transmit andreceive signals to and from other devices or equipment, device 10 mayinclude alignment structures 152-1 and 152-2 (sometimes referred toherein as attachment structures). Alignment structures 152-1 and 152-2may include magnetic structures or magnets that overlap rear housingwall 12R. If desired, alignment structures 152-1 and 152-2 may be formedfrom non-magnetic structures such as posts, pins, clips, springs,brackets, holes, etc., or any other suitable alignment structures.

In some exemplary configurations, alignment structures 152-1 and 152-2may be incorporated into rear housing wall 12R, may be mounted directlyto rear housing wall 12R, may be adhered to rear housing wall 12R, ormay be formed at any suitable location overlapping rear housing wall12R. Alignment structures 152-1 and 152-2 may bias rear housing wall andthus device 10 against other alignment structures in other devices orequipment (e.g., device 130 in FIG. 6 with which device 10 may wirelesscommunicate). In other words, the alignment structures 152-1 and 152-2may lock or fix the relative position of device 10 in one or more of theX, Y, and Z directions with respective to another device or equipment(via a magnetic force or any other suitable force).

In the example of FIG. 7 , alignment structure 152-1 may be interposedbetween the top sidewall 12W and the top portion of electrode 150, andalignment structure 152-2 may be interposed between the bottom sidewall12W and the bottom portion of electrode 150. If desired, some or all ofthe antenna elements of antennas 40-2 or 40-3 (e.g., antenna elements156-1 and 156-3, or antenna elements 154-1 and 154-2) may be formedalong the same axis (e.g., the X-axis) as alignment structures 152. Ifdesired, some or all of the antenna elements of antennas 40-2 or 40-3(e.g., antenna elements 156-2 and 156-4) may be formed along an axis(e.g., the Y-axis) that is perpendicular to the axis (e.g., the X-axis)along which alignment structures 152 lie.

As examples, attachment structures 152-1 and/or 152-2 may overlap only aplanar portion of rear housing wall 12R outside of dashed circle 72, mayoverlap only a protruding portion of rear housing wall 12R inside ofdashed circle 72, or may overlap both the planar portion and theprotruding portion of rear housing wall 12R. In the example of FIG. 7 ,attachment structures 152-1 and 152-2 have a rectangular shape oroutline. However, these examples are merely illustrative. If desired,these attachment structures in device 10 may have a suitable shape oroutline, may be located any suitable location, may include any number ofseparate structures, etc.

FIG. 8 is a top-down view of an illustrative electronic device such asdevice 130 (FIG. 6 ) having alignment or attachment structuresconfigured to align device 130 with and attach device 130 to otherdevices such as device 10 (FIG. 7 ). In the example of FIG. 8 , device130 may be equipment that is coupled to power adapter circuitry using acable such as cable 164, through which device 130 receives power. Ifdesired, device 130 may be a stand-alone charger. Power transmittingdevice 130 may include power transmitting circuitry for transmittingwireless power to a wireless power receiving device such as device 10.

Device 130 may have a housing with a cylindrical shape and may thereforehave a circular top-down outline. If desired, device 130 may have anyother suitable shape. The top surface or the housing at the top surfaceof device 130 (sometime referred to herein as the top surface housing orhousing portion of device 130) may have a depressed or recessed portionwithin dashed circle 168 and may have a planar portion outside dashedcircle 168. In other words, the top surface housing portion of device130 outside of dashed circle 168 may lie substantially in a flat plane(e.g., the plane of the page in FIG. 8 , the X-Y plane) and the topsurface housing portion of device 130 inside of dashed circle 168 may berecessed from the plane in the −Z direction (e.g., into the page in FIG.7 ). As an example, the recessed portion of device 130 may accommodatefor the protruding portion of rear housing wall 12R in device 10 (FIG. 7) such that when the rear housing wall of device 10 is placed onto thetop surface housing of device 130, device 10 may be placed in arelatively flush manner on device 130.

Device 130 may include one or more coils such as coil structures 166that overlap the recessed top surface portion of the housing. Coilstructures 166 in device 130 may align with coil structures 44 in device10 (e.g., coils 96 in device 10 of FIG. 7 ). Device 130 may includepower transmitting circuitry, control circuitry, and other componentsoperable to perform wireless power transmission functions using coilstructures 166. In the example of FIG. 8 , coil structures 166 mayoverlap a central location of the top surface housing. This is merelyillustrative. If desired, coil structures 166 may be formed at anysuitable location.

Additionally, device 130 may include wireless circuitry 134 (FIG. 6 )having antennas 138-1 and/or 138-2. In the illustrative examplesdescribed herein, device 130 may include either antenna 138-1 or antenna138-2. This is merely illustrative. If desired, device 130 may includeboth antennas 138-1 and 138-2 as illustrated in FIG. 8 .

Antenna 138-1 may include separate antenna structures such as antennaresonating elements 174-1, 174-2, 174-3, and 174-4 (sometimes referredto herein as antenna elements) that are disposed along the peripheralsides of device 130 outside of the recessed top surface portion of thehousing. Antenna 138-2 may include separate antenna structures such asantenna resonating elements 172-1 and 172-2 (sometimes referred toherein as antenna elements) that overlap the recessed top surfacehousing portion. As examples, antenna elements for antenna 138-1 indevice 130 may be operable to transmit and receive radio-frequencysignals to and from antenna 40-3 in device 10, and antenna elements forantenna 138-2 in device 130 may be operable to transmit and receiveradio-frequency signals to and from antenna 40-2 in device 10.

Respective radio-frequency transceiver circuitries 136 in wirelesscircuitry 134 (FIG. 6 ) may be coupled to antennas 138-1 and 138-2.Radio-frequency transceiver circuitries 136 may be coupled to antennas138-1 and 138-1 in the analogous manner as described for wirelesscircuitry 34 in connection with FIG. 3 . These descriptions are omittedin order to not unnecessarily obscure the embodiments of FIG. 8 .

Furthermore, antenna resonating elements for antenna 138-1 and/orantenna 138-2 may be formed from dipole antenna element such as thedipole antenna element shown in FIG. 5 . This is merely illustrative. Ifdesired, antenna resonating elements for antennas 138-1 and/or 138-2 maybe formed from patch antenna resonating elements, inverted-F antennaresonating elements, planar inverted-F antenna resonating elements,monopole resonating elements, dipole resonating elements, loopresonating elements, another type of antenna resonating element, and/ora combination of these types of antenna resonating elements.

To ensure antennas 138-1 and/or 138-2 may effectively transmit andreceive signals to and from a communicating device, alignment structures170-1 and 170-2 (sometimes referred to herein as attachment structures)such as magnetic structures or magnets may overlap the top surfacehousing of device 130. If desired, alignment structures 170-1 and 170-2may be formed from non-magnetic structures or any other suitablealignment structures.

In some exemplary configurations, structures 170-1 and 170-2 mayincorporated into the top housing wall of device 130, may be mounteddirectly to the top housing wall of device 130, may be adhered to rearhousing wall 12R, may be formed at any suitable location overlapping thetop housing wall of device 130. Alignment structures 170-1 and 170-2 maybias the top housing wall and hence device 130 against other alignmentstructures in devices or equipment (e.g., device 10 in FIG. 7 with whichdevice 130 may wireless communicate). In other words, the alignmentstructures 170-1 and 170-2 may lock or fix the relative position ofdevice 130 in the X, Y, and Z directions with respective to anotherdevice or equipment (via a magnetic force or any other suitable force).

In the example of FIG. 8 , alignment structure 170-1 may be interposedbetween an upper edge portion of device 130 and coil structures 166, andalignment structure 170-2 may be interposed between a lower edge portionand coil structures 166. If desired, some or all of the antenna elementsof antennas 138-1 or 138-2 (e.g., antenna elements 172-1 and 172-2, orantenna elements 174-1 and 174-3) may be formed along the same axis(e.g., the X-axis) as alignment structures 170. If desired, some or allof the antenna elements of antennas 138-1 or 138-2 (e.g., antennaelements 174-2 and 174-4) may be formed along an axis (e.g., the Y-axis)that is perpendicular to the axis (e.g., the X-axis) along whichalignment structures 170 lie.

As examples, attachment structures 170-1 and/or 170-2 may overlap only aplanar portion of the top surface housing outside of dashed circle 168,may overlap only a recessed portion of the top surface housing inside ofdashed circle 168, or may overlap both the planar portion and therecessed portion of the top surface housing of device 130. In theexample of FIG. 8 , attachment structures 170-1 and 170-2 may have arectangular shape or outline. However, these examples are merelyillustrative. If desired, these attachment structures in device 130 mayhave a suitable shape or outline, may be located any suitable location,may include any number of separate structures, etc.

Referring to both FIGS. 7 and 8 when device 10 is placed on top ofdevice 130 such that the rear surface of device 10 is adjacent to(overlapping) the top surface of device 130, regardless of therotational orientation about the Z-axis, magnetic structures 152-1 and152-2 in device 10 and magnetic structures 170-1 and 170-2 in device 10may forcibly align the rotational orientation of device 10 to device 130and attach device 10 to device 130. In particular, magnetic forces ornon-magnetic forces may rotate device 10 clockwise or counterclockwiseabout the Z-axis such that magnetic structures 152-1 and 170-1 arealigned (e.g., overlap in the Z-direction) and magnetic structures 152-2and 170-2 are aligned (e.g., overlap in the Z-direction) or such thatmagnetic structures 152-1 and 170-2 are aligned (e.g., overlap in theZ-direction) and magnetic structures 152-2 and 170-1 are aligned (e.g.,overlap in the Z-direction). In either of these two alignment statesantennas 40-2 and 138-2 (e.g., antenna resonating elements in antennas40-2 and 138-2) may be satisfactorily aligned (e.g., have satisfactorysignal polarization alignment, have satisfactory directional alignment,etc.) to perform reliable wireless communications such as near-fieldhigh data rate data transfer operations and/or antennas 40-3 and 138-1(e.g., antenna resonating elements in antennas 40-2 and 138-2) may besatisfactorily aligned to perform reliable wireless communications suchas near-field high data rate data transfer operations.

The configurations of device 10 in FIG. 7 and device 130 in FIG. 8 aremerely illustrative. If desired one or more antenna resonating elementsmay be omitted from one or both of devices 10 and 130. If desired,devices 10 and 130 may have different numbers of antenna resonatingelements operable to perform high data rate data transfer operations. Asan example, device 10 may have only two separate antenna resonatingelements operable to perform data transfer operations with device 130,while device 130 may have four separate antenna resonating elements, ofwhich two are active and two are inactive when devices 10 and 130 aresatisfactorily aligned using attachment structures.

If desired, devices 10 and 130 may have other corresponding alignmentstructures in addition to or instead of magnetic structures 152-1,152-2, 170-1, and 170-2. If desired, a single continuous attachmentstructure may be disposed within each of devices 10 and 130 foralignment (instead of two separate magnetic structures as shown in FIGS.7 and 8 ). If desired, more than two separate attachment structures maybe disposed within each of devices 10 and 130 for alignment. In someconfigurations, (magnetic) alignment or attachment structures such asstructures 152-1, 152-2, 170-1, and 170-2 may be omitted from devices 10and 130. In some configurations and in the absence of these alignment orattachment structures, devices 10 and 130 may still be operable toachieve satisfactory alignment for wireless communications (e.g., forhigh data rate data transfer operations).

FIGS. 9 and 10 show how a first device such as device 10 and a seconddevice such as device 130 may be configured to satisfactorily establishand maintain wireless communication links for high data rate datatransfer operations without dedicated alignment or attachmentstructures. FIG. 9 is a bottom-up view of an illustrative electronicdevice such as device 10 (in FIG. 6 ) having one or more arrays ofantenna elements operable to wirelessly communicate with other devicessuch as device 130 (in FIG. 6 ).

As a first example, device 10 may include an antenna array (e.g.,antenna 40-2 or sometimes referred to herein as antenna array 40-2)formed from antenna resonating elements 154-1, 154-2, 154-3, 154-4,154-5, 154-6, 154-7, and 154-8 (sometimes referred to collectively asantenna resonating elements 154). Antenna resonating elements 154 may beformed in a circumferential pattern surrounding a central axis of device10 (e.g., central axis 94 in FIG. 4 ), may be disposed along acircumferential path from the central axis of device 10, may be disposedequidistantly from the central axis of device 10, etc. In particular,antenna resonating elements 154 may be formed around the peripheraledges of backside circuitry module 88. If desired, antenna resonatingelements 154 may overlap the protruding portion of the rear wallhousing, may be laterally surrounded by coil(s) 96 (shown in FIG. 7 ,omitted from FIG. 9 for clarity) and sensor electrodes 150, and maylaterally surround portions of backside circuitry module 88 (e.g.,sensors 92).

Antenna resonating elements 154 may be coupled to the sameradio-frequency transceiver circuitry 48 (FIG. 6 ) such as near-fieldcommunications circuitry and/or centimeter wave and millimeter wavetransceiver circuitry and may be operable in pairs (e.g., pairs ofantenna resonating elements 154-1 with 154-3, 154-2 with 154-4, 154-5with 154-7, and 154-6 with 154-8). The pairs may implement a half-duplexsystem or a full duplex system. The two antenna resonating elements ineach pair may be disposed on opposing sides of backside circuitry module88.

As a second example, device 10 may include an antenna array (e.g.,antenna 40-3 or sometimes referred to herein as antenna array 40-3)formed from antenna resonating elements 156-1, 156-2, 156-3, 156-4,156-5, 156-6, 156-7, and 157-8 (sometimes referred to collectively asantenna resonating elements 156). Antenna resonating elements 156 may beformed in a circumferential pattern surrounding a central axis of device10 (e.g., central axis 94 in FIG. 4 ), may be disposed along acircumferential path from the central axis of device 10, may be disposedequidistantly from the central axis of device 10, etc. In particular,antenna resonating elements 156 may be formed near or at the peripheraledges of rear housing wall 12R. If desired, antenna resonating elements154 may overlap the planar portion (e.g., the non-protruding portion ofrear housing wall 12R), may be laterally surround electrodes 150,coil(s) 96 (FIG. 7 ), and backside circuitry module 88.

Antenna resonating elements 156 may be coupled to the sameradio-frequency transceiver circuitry 48 (FIG. 6 ) such as near-fieldcommunications circuitry and/or centimeter wave and millimeter wavetransceiver circuitry and may be operable in pairs (e.g., pairs ofantenna resonating elements 156-1 with 156-3, 156-2 with 156-4, 156-5with 156-7, and 156-6 with 156-8). The pairs may implement a half-duplexsystem or a full-duplex system. The two antenna resonating elements ineach pair may overlap on opposite sides of rear housing wall 12R.

These examples are merely illustrative. If desired, antenna resonatingelements 154 and/or 156 may be formed in any suitable pattern to overlaprear housing wall 12R. If desired, antenna resonating elements 154and/or 156 may include any suitable number of separate antennasresonating elements that form antenna arrays 40-2 and/or 40-3. Ifdesired, antenna resonating elements 154 and/or 156 may operatesingularly or collectively as suitable.

FIG. 10 is a top-down view of an illustrative electronic device such asdevice 130 (in FIG. 6 ) having one or more arrays of antenna elementsoperable to wirelessly communicate with other devices such as device 10(in FIG. 8 ).

As a first example (e.g., congruent with the first example for device 10in FIG. 9 ), device 130 may include an antenna array (e.g., antenna138-2 or sometimes referred to herein as antenna array 138-2) formedfrom antenna resonating elements 172-1, 172-2, 172-3, 172-4, 172-5,172-6, 172-7, and 172-8 (sometimes referred to collectively as antennaresonating elements 172). Antenna resonating elements 172 may be formedin a circumferential pattern surrounding a central axis of device 130(e.g., an axis that runs orthogonally from a center point in thecircular outline of device 130 in the Z-direction), may be disposedalong a circumferential path from the central axis of device 130, may bedisposed equidistantly from the central axis of device 130, etc. Ifdesired, antenna resonating elements 172 may overlap the planar portion(e.g., a non-recessed portion) of the top surface housing (e.g., outsideof dashed circle 168) and may be laterally surround coil structures 166.

Antenna resonating elements 172 may be coupled to the sameradio-frequency transceiver circuitry 136 (FIG. 6 ) such as near-fieldcommunications circuitry and/or centimeter wave and millimeter wavetransceiver circuitry and may be operable in pairs (e.g., pairs ofantenna resonating elements 172-1 with 172-3, 172-2 with 172-4, 172-5with 172-7, and 172-6 with 172-8). The pairs may implement a half-duplexsystem or a full duplex system. The two antenna resonating elements ineach pair may overlap opposite sides of the top surface housing ofdevice 130.

As a second example (e.g., congruent with the second example for device10 in FIG. 9 ), device 130 may include an antenna array (e.g., antenna138-1 or sometimes referred to herein as antenna array 138-1) formedfrom antenna resonating elements 174-1, 174-2, 174-3, 174-4, 174-5,174-6, 174-7, and 174-8 (sometimes referred to collectively as antennaresonating elements 174). Antenna resonating elements 174 may be formedin a circumferential pattern surrounding a central axis of device 130(e.g., an axis that runs orthogonally from a center point in thecircular outline of device 130), may be disposed along a circumferentialpath from the central axis of device 130, may be disposed equidistantlyfrom the central axis of device 130, etc. If desired, antenna resonatingelements 174 may overlap the recessed portion of top surface housing(e.g., within dashed circle 168, may be laterally surround or belaterally surrounded by coil structures 166.

Antenna resonating elements 174 may be coupled to the sameradio-frequency transceiver circuitry 136 (FIG. 6 ) such as near-fieldcommunications circuitry and/or centimeter wave and millimeter wavetransceiver circuitry and may be operable in pairs (e.g., pairs ofantenna resonating elements 174-1 with 174-3, 174-2 with 174-4, 174-5with 174-7, and 174-6 with 174-8). The pairs may implement a half-duplexsystem or a full duplex system. The two antenna resonating elements ineach pair may overlap opposite sides of the top surface housing ofdevice 130.

These examples are merely illustrative. If desired, antenna resonatingelements 172 and/or 174 may be formed in any suitable pattern to overlapthe top surface housing of device 130. If desired, antenna resonatingelements 172 and/or 174 may include any suitable number of separateantennas resonating elements that form antenna arrays 138-2 and/or138-1. If desired, antenna resonating elements 172 and/or 174 mayoperate singularly or collectively as suitable.

By providing antenna array 40-2 on device 10 and antenna array 138-2 ondevice 130, regardless of the rotational orientation about the Z-axis ofdevice 10 with respect to device 130, at least one pair of antennaresonating elements from each device may be satisfactorily aligned toperform wireless communication.

FIG. 11 is an illustrative flowchart for establishing wirelessconnections between two devices such as devices 10 and 130. As anexample, control circuitry on devices 10 and/or 130 in FIGS. 9 and 10may process one or more steps in FIG. 11 to establish and maintainwireless connections between each other. At step 182, a first device(e.g., a wireless power receiving device 10) may be placed on a seconddevice (e.g., a wireless power transmitting device 130). As an example,the housing at the top surface of device 130 having a recessed portionmay receive rear housing wall 12R (FIG. 9 ) of device 10 having aprotruding portion.

Optionally, at step 184, alignment or attachment structures such asstructures 152 and 170 in FIGS. 7 and 8 or other structures may aligndevice 10 with respective to the device 130 via attachment structuressuch as magnetic attachment structures. In some configurations, thisalignment may already enable devices 10 and 130 to satisfactorilycommunicate wirelessly with each other (e.g., as described in connectionwith FIGS. 7 and 8 ). If desired, a single set of structures may biasdevice 10 to device 130 along the Z-axis but does not fix the relativelyrotational orientation of devices 10 and 130 about the Z-axis.

At step 186, device 130 (e.g., control circuitry 132 in device 130) maydetect the presence of device 10 and determine that wirelesscommunications between devices 10 and 130 may be enabled. As an example,device 130 may operable in a device discovery mode, during which anantenna (e.g., one or more antenna elements on an antenna array) ondevice 130 may continually transmit and/or monitor the reception ofradio-frequency signals (e.g., to and/or from device 10). When aresponse to a transmitted radio-frequency signals is received, device130 may determine that device 10 is present and is ready for wirelesscommunication. As another example, device 130, after detecting thephysical presence of device 10, may trigger a wireless power wake-upsignal useable to activate wireless power transmitting circuitry indevice 130. The same wireless power wake-up signal may be used to promptwireless communications between devices 10 and 130.

At step 188, device 130 (e.g., control circuitry 132 in devices 130) maydetermine one or more optimal antenna elements (e.g., on both devices 10and 130). Using these one or more optimal antenna elements, devices 10and 130 may establish a wireless communication link. In particular,device 130 may identify (e.g., receive, gather, and/or generate)corresponding performance metrics (sometimes referred to herein aswireless performance information) for each antenna element or eachantenna element pair in device 130 when linked with a correspondingantenna element or corresponding antenna element pair in device 10.Device 130 may then compare the identified corresponding performancemetrics to each other and/or to a performance metric threshold level. Ifdesired, performance metrics may be identified in combination with step186 (e.g., in the device discovery mode of operation for device 130).

These performance metrics may include received power, receiversensitivity, receive band noise (e.g., a receive band noise floorvoltage level), frame error rate, bit error rate, packet error rate,channel quality measurements based on received signal strength indicator(RSSI) information, adjacent channel leakage ratio (ACLR) information(e.g., ACLR information in one or more downlink frequency channels),channel quality measurements based on received signal code power (RSCP)information, channel quality measurements based on reference symbolreceived power (RSRP) information, channel quality measurements based onsignal-to-interference ratio (SINR) and signal-to-noise ratio (SNR)information, channel quality measurements based on signal quality datasuch as Ec/Io or Ec/No data, or any other suitable type of performancemetrics.

As an example, one or both antenna resonating elements in pairs ofantenna resonating elements in antenna 138-2 (FIG. 10 ) may transmitradio-frequency signals. One or both antenna resonating elements inpairs of antenna resonating elements in antenna 40-2 (FIG. 9 ) mayreceive the transmitted radio-frequency signals and in response transmita response (radio-frequency) signal. This may occur sequentially foreach pair of antenna resonating elements in antenna 138-2 and/or foreach pair of antenna resonating elements in antenna 40-2. Signals fromcorresponding pairs of antenna resonating elements in antenna 138-2 maybe used as measurements to obtain performance metrics based on thereceived response signal. If desired, testing may be performed for pairsof antenna resonating elements in a radial pattern (e.g., testing thepair of antenna elements that include elements 154-1 and 154-3, the pairof antenna elements that include elements 154-6 and 154-8, the pair ofantenna elements that include elements 154-2 and 154-4, etc. in FIG. 9). If desired, during testing one or more (or all) of antenna resonatingelements 172 may be operable to detect signals transmitted from eachseparate pair of antenna resonating elements 154.

This example is merely illustrative. If desired, any other testingscheme and/or performance metrics gathering scheme may be used todetermine one or more optimal antenna resonating elements. While thisexample uses antennas 138-2 and 40-2, similar operations may useantennas 138-1 and 40-3 in addition to or instead of antenna 138-2 and40-2.

At step 190, device 130 (e.g., control circuitry 132 in devices 130) mayperform device pairing for wireless communications to establish thewireless communication link using the one or more optimal antennaelements on devices 10 and 130. As an example, device 130 may activelyuse optimal antenna resonating elements 174-1 and 174-3 and disableantenna resonating elements 174-2, 174-4, 174-5, 174-6, 174-7, and174-8. Similarly, device 10 may actively use optimal antenna resonatingelements 156-5 and 156-7 (which may be aligned with antenna resonatingelements 174-1 and 174-3) and disable antenna resonating elements 156-1,156-2, 156-3, 156-4, 156-6, and 156-8. If desired, device 130 mayconfigure the wireless communication link to optimize for communicationwith device and/or for any suitable application for which the wirelesscommunication link is established.

At step 192, device 130 may perform data transfer operations (as anexample) with device 10 using the established wireless communicationlink. In particular, the established wireless communication link may beas a high data rate, bi-directional, and near-filed wirelesscommunication link through which data transfer operations may beperformed.

If desired, at step 194, device 130 (e.g., control circuitry 132 indevices 130) may (periodically) determine whether the one or moreantenna elements selected in steps 188 remain optimal. If desired, step194 may be performed when relative low amounts of data are beingtransferred between devices 10 and 130. If desired, step 194 may beperformed at regular time intervals. If desired, step 194 may beperformed when movement of at least one of devices 10 and/or 130 isdetected. In response, devices 10 and 130 may re-establish the wirelesscommunication link based on one or more updated and optimal antennaelements on devices 10 and/or 130. As an example, device 130 may performstep 188 to determine the one or more updated and optimal antennaelements. If desired, devices 130 may also (periodically) determinewhether settings for the established wireless communication link shouldbe updated and re-establish the wireless communication link using theupdated settings.

These steps are merely illustrative. If desired, control circuitry 28 ondevice 10 (FIG. 6 ) may process one or more steps to determine optimalantenna resonating elements (instead of control circuitry 132 on device130).

FIG. 12 is a diagram of illustrative states (e.g., modes of operation)for device 130 (e.g., for wireless circuitry 134 and/or controlcircuitry 132 in FIG. 6 ) when performing data transfer operations withdevice 10. In particular, prior to any interaction with device 10,device 130 may be in a radio-frequency circuitry idle state 202, inwhich one or more portions or all of wireless circuitry 132 is inactive.In response to determining that device 10 is nearby (e.g., adjacent todevice 130), device 130 may be in a device detection and pairing state204, in which device 130 may determine an optimal set of antennaelements both on device 130 and on device 10 through which devicepairing and an establishment of a wireless communication link may occur(e.g., steps 186-190 in FIG. 11 ). After pairing device 130 with device10, device 130 may be in a mode configuration state 206, in which device130 may configure settings (e.g., use application-specific protocols,tune antenna elements, switch between different duplexing modes,determine transmit power, etc.) for the established wirelesscommunication link. After the wireless communication link is configured,device 130 may be in a data transfer state 208, during which data may befreely conveyed between devices 130 and 10 (e.g., step 192 in FIG. 11 ).Device 130 may return to idle state 202 when device 10 is removed fromthe proximity of device 130, when data transfer operations are no longernecessary, etc.

In an exemplary configuration, a user may place the first device ontothe second device without having to focus on perfectly aligning thefirst device to the second device (e.g., about the Z-axis). In a firstexample, the alignment or attachment structures may exhibit forces thatautomatically align the first and second devices when the first deviceis placed onto the second device, thereby aligning the wirelesscircuitries (e.g., antennas) of the first and second devices andconfiguring the first and second devices to form a reliable wirelesscommunication link. In a second example, the first and/or second devicemay determine one or more optimal antenna elements or pairs of antennaelements in antenna arrays on the first and second devices based on theimperfectly aligned orientation between the first and second devices.The one or more optimal antenna elements or pairs of antenna elements inantenna arrays on the first and second devices may then be used to forma reliable wireless communication link.

By providing alignment or attachment structures and/or antenna arrays onfirst and second communicating devices (e.g., as described in connectionwith FIGS. 6-12 ), high data rate, near-field wireless communicationlinks may be robustly established between the first and secondcommunicating devices.

The foregoing is merely illustrative and various modifications can bemade to the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. An electronic device having first and secondfaces comprising: a display at the first face; a housing having ahousing wall at the second face; first and second antenna resonatingelements that overlap the housing wall and that are operable to conveyradiofrequency signals at a frequency above 10 GHz through the housingwall; and magnetic structures disposed in the housing and configured toapply a magnetic force through the housing wall to fix a position of theelectronic device relative to external equipment.
 2. The electronicdevice defined in claim 1, wherein the magnetic structures comprise afirst magnet that overlaps the housing wall at a first location and asecond magnet that overlaps the housing wall at a second location. 3.The electronic device defined in claim 2, wherein the first and secondmagnets are configured to bias the housing wall against the externalequipment and to align the first and second antenna resonating elementswith corresponding antenna elements on the external equipment.
 4. Theelectronic device defined in claim 1 further comprising: near-fieldcommunications circuitry coupled to the first and second antennaresonating elements and configured to use the first and second antennaresonating elements to convey the radio-frequency signals at thefrequency above 10 GHz through the housing wall.
 5. The electronicdevice defined in claim 4 further comprising: a substrate disposedbetween the display and the housing wall, the first and second antennaresonating elements being formed at the substrate.
 6. The electronicdevice defined in claim 1 further comprising: an additional antennaresonating element that overlaps the housing wall and that is operableto convey additional radio-frequency signals at an additional frequencybelow 10 GHz through the housing wall, wherein the additional antennaresonating element at least partly defines an antenna aperture and thefirst antenna resonating element is aligned with the antenna aperture.7. The electronic device defined in claim 1 further comprising: a sensormodule, wherein the magnetic structures are disposed on opposing sidesof the sensor module; a coil structure that surrounds the sensor module;and wireless power receiving circuitry coupled to the coil structure andconfigured to use the coil structure to receive wireless power signalsthrough the housing wall.
 8. The electronic device defined in claim 7,wherein the housing wall is a rear housing wall, the first and secondantenna resonating elements form an antenna array, and the magneticstructures are configured to bias the electronic device against theexternal equipment with the magnetic force.
 9. The electronic devicedefined in claim 1, wherein the electronic device is a wristwatchdevice, the first and second faces are opposing faces, and the first andsecond antenna resonating elements form an antenna array, the electronicdevice further comprising: radio-frequency transceiver circuitry coupledto the first and second antenna resonating elements and configured touse the first and second antenna resonating elements to convey theradio-frequency signals at the frequency above 10 GHz through thehousing wall.
 10. A wristwatch device having first and second opposingfaces comprising: a display at the first face; a rear housing member atthe second face; an antenna array having a plurality of antennaresonating elements that overlap the rear housing member;radio-frequency transceiver circuitry coupled to the plurality ofantenna resonating elements and configured to convey radio-frequencysignals at a frequency above 10 GHz through the rear housing memberusing the plurality of antenna resonating elements; and alignmentstructures configured to apply a force across the rear housing member tofix a position of the wristwatch device relative to external equipment.11. The wristwatch device defined in claim 10, wherein the plurality ofantenna resonating elements are circumferentially distributed about anaxis.
 12. The wristwatch device defined in claim 11 further comprising:sensor circuitry, wherein the plurality of antenna resonating elementssurround the sensor circuitry; and a coil that surrounds the sensorcircuitry.
 13. The wristwatch device defined in claim 10, wherein theradio-frequency transceiver circuitry comprises near-fieldcommunications circuitry, the near-field communications circuitry beingconfigured to convey the radio-frequency signals at the frequency above10 GHz through the rear housing member using the plurality of antennaresonating elements.
 14. The wristwatch device defined in claim 13,wherein the near-field communications circuitry is configured to conveythe radio-frequency signals at the frequency above 10 GHz through therear housing member using only a subset of the plurality of antennaresonating elements at a given time.
 15. The wristwatch device definedin claim 13, wherein the near-field communications circuitry isconfigured to convey the radio-frequency signals at the frequency above10 GHz through the rear housing member using a first pair of the antennaresonating elements in the plurality of antenna resonating elements at afirst time and a second pair of the antenna resonating elements in theplurality of antenna resonating elements at a second time.
 16. Thewristwatch device defined in claim 10 further comprising: a backsidecircuitry module having a substrate, to which the radio-frequencytransceiver circuitry is mounted, wherein the plurality of antennaresonating elements are formed at the substrate.
 17. The wristwatchdevice defined in claim 10 further comprising: control circuitry; and aprinted circuit substrate to which the control circuitry and theradio-frequency transceiver circuitry are mounted, wherein the pluralityof antenna resonating elements are formed at the printed circuitsubstrate.
 18. An electronic device comprising: a housing having a rearhousing wall; a coil structure; wireless power receiving circuitrycoupled to the coil structure and configured to use the coil structureto receive wireless power signals through the rear housing wall; aplurality of antenna elements for an antenna array operable to conveyradio-frequency signals through the rear housing wall; and alignmentstructures configured to bias the electronic device toward externalequipment with a force applied across the rear housing wall to fix aposition of the electronic device relative to the external equipment.19. The electronic device defined in claim 18 further comprising:near-field communications circuitry coupled to the antenna array andconfigured to use the antenna array to convey the radio-frequencysignals at a frequency above 10 GHz.
 20. The electronic device definedin claim 18 further comprising: a display; and a substrate disposedbetween the display and the rear housing wall, wherein at least aportion of the plurality of antenna elements are embedded within thesubstrate.